Calculators
Online Calculators
539 tools
Browse by subject.
Popular calculators
High-traffic and flagship tools. Registry featured list.
- Ohm's Law Calculator Enter any two of voltage, current, resistance, and power to solve the remaining values. Runs locally in your browser. Free online tool — no sign-up.
- Watts to Amps Calculator Convert watts to amps (and reverse) for DC, single-phase, and three-phase circuits. Power factor and voltage inputs included for AC loads. Try it free.
- Smith Chart Calculator Interactive impedance Smith chart with auto-match, drag-to-tune, L·C·R / T-line / stub / transformer / ‖RLC, Custom Z(f), f-locus, and Touchstone S11/S21 with stability overlays. Runs locally in your browser.
- Free-Space Path Loss Calculator Compute free-space path loss FSPL = 20·log10(d·f) + 20·log10(4π/c) from distance and frequency, with optional antenna gains. Runs locally in your browser.
- Voltage Divider Calculator Solve a two-resistor voltage divider: enter exactly three of Vin, R1, R2, and Vout to find the fourth. Also reports current, power, ratio, and Rth. Try it free.
- Percentage Calculator Calculate percentages, percentage of a number, and “what percent is X of Y” with clear arithmetic steps. Runs locally in your browser. Try it free.
- Uncertainty Propagation Calculator Propagate measurement uncertainty using GUM linear propagation, covariance, uncertainty budgets, or Monte Carlo simulation. Optional correlation ρ and coverage factor k → U. Runs locally in your browser.
- GPA Calculator Calculate GPA from letter grades and credit hours using a 4.33 or 4.0 reference scale, with an optional Custom A+ value. Runs locally in your browser. Free online tool — no sign-up.
Grade calculators
GPA, final grade, and letter grade conversions.
- Final Grade Calculator Find the score you need on a final exam, compute your overall grade after the final, run a weighted category average, or convert point totals into final.
- GPA Calculator Calculate GPA from letter grades and credit hours using a 4.33 or 4.0 reference scale, with an optional Custom A+ value. Runs locally in your browser. Free online tool — no sign-up.
- GPA to Letter Grade Calculator Approximate GPA-to-letter interpretation on plus/minus 4.33, flat 4.0, or linear 5.0 normalization, with explicit tie-breaks, example percentage bands, and range validation.
- Letter Grade to GPA Calculator Convert a letter grade (A+ to F) to published grade points on plus/minus 4.33 or flat 4.0. Optional credits show quality points for one course.
Math calculators
Arithmetic, percentages, trigonometry, and more.
- Absolute Value Calculator Solve absolute value equations in one variable. Find zero, one, two, or infinitely many solutions, preserve small roots, and share or export the full result.
- Absolute Value Inequality Calculator Solve absolute value inequalities with open or closed bounds. Inspect bounded intervals, unions, and degenerate cases, then share or export the solution set.
- Angle Between Lines Calculator Find the smaller angle between two planar lines in degrees and radians. Check parallel or perpendicular status, numerical limits, figures, sharing and exports.
- Annulus Calculator Calculate annulus area and perimeter with complete numerical results, clear input limits, shareable links and CSV export. Runs locally in your browser.
- Antilog Calculator Calculate x = b^y with base 10, e, 2 or any positive base except 1. Explore examples, precision limits and comparison tables, then share or export results.
- Arc Calculator Calculate circular arc length from radius and central angle in degrees. See the radian formula, worked examples, units, and mathematical sources.
- Arccos Calculator Calculate the principal arccosine in degrees and radians. Explore its graph, exact common angles, input limits, worked examples, and NIST reference sources.
- Arcsin Calculator Calculate the principal arcsine in degrees and radians. Explore its graph, exact common angles, input limits, worked examples, and NIST reference sources.
- Arctan Calculator Calculate the principal arctangent in degrees and radians. Explore its graph, exact common angles, rounding limits, worked examples, and NIST references.
- Arithmetic Sequence Calculator Find an exact integer arithmetic sequence term and finite sum from the first term, common difference and index. Check limits, worked steps and full exports.
- Bessel I Calculator Evaluate modified Bessel I functions for integer orders 0–8. Explore a live graph, worked examples, input limits and shareable results computed locally.
- Bessel J Calculator Evaluate integer-order Bessel J functions for orders 0–8. Explore a live graph, worked examples, input limits and shareable results computed locally.
- Bessel K Calculator Evaluate modified Bessel K functions for positive x, orders 0–8. Explore a live graph, worked examples, input limits and shareable results computed locally.
- Bessel Y Calculator Evaluate Bessel Y functions for positive x and orders 0–8. Explore a live graph, worked examples, input limits and shareable results computed locally.
- Beta Function Calculator Calculate the complete Euler beta function B(x,y). Explore a live graph, worked examples, input limits and shareable results computed locally.
- Brent Method Calculator Brent’s method (golden section plus inverse parabolic interpolation) for a minimum of a polynomial, sin, or exp on [a, b]. Same engine as One-Dimensional Optimization. Not root-finding Brent. Runs locally.
- Cholesky Factorization Calculator Lower Cholesky factorization of a small real symmetric positive-definite matrix. Same engine as Linear System. Not LU. Not a CAS. Runs locally.
- Circle Calculator Calculate circle radius, diameter, circumference, area, arc length, and sector area. Explore formulas, worked examples, units, and mathematical sources.
- Column Space Calculator Column space (image) of a small real square matrix from RREF pivot columns. Same engine as Linear System. Trivial image is {0}. Left-nullspace is a sibling. Runs locally.
- Complex Number Calculator Add, subtract, multiply and divide complex numbers. Convert polar forms, calculate integer powers and all nth roots, with an Argand diagram and numeric limits.
- Complex Polar Calculator Convert complex numbers between rectangular and polar forms in degrees. Inspect the modulus, principal argument, Argand diagram, worked examples and limits.
- Complex Power Calculator Calculate positive, zero and negative integer powers of complex numbers. View rectangular and polar results, an Argand diagram, examples and numerical limits.
- Complex Roots Calculator Calculate every nth root of a complex number and identify the principal root. View all roots on an Argand diagram, export complete results and inspect limits.
- Condition Number Calculator κ₁(A) = ‖A‖₁ ‖A⁻¹‖₁ for a small real square matrix. Same engine as Linear System. Singular matrices return infinite. Not a 2-norm product. Runs locally.
- Cone Calculator Calculate measures for a right cone with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Conic Section Calculator Explore ellipse, parabola and hyperbola geometry: calculate foci, eccentricity and equations, inspect numerical limits, and share or export complete results.
- Coordinate Geometry Calculator Calculate planar distance, midpoint, slope and line relationships. Inspect formulas, numerical limits, figures, share links and full coordinate results locally.
- Cos Calculator Calculate cosine from degrees, radians, or triangle side ratios. Inspect numerical limits, share precise inputs, export results, and call the REST or MCP API.
- Cross Product Calculator Calculate vector cross products in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Cubic Equation Calculator Solve real cubic equations with Cardano and trigonometric forms. Inspect all three roots, repeated roots, numerical limits, share inputs, and export results.
- Cylinder Calculator Calculate measures for a right cylinder with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Definite Integral Calculator Composite trapezoid, Simpson 1/3, or Gauss–Legendre of a polynomial, sin, or exp on [a, b]. Not indefinite symbolic integrate. Runs locally.
- DFT Calculator Compute the direct DFT for real or complex sequences of 1–64 samples. Inspect every frequency bin and magnitude, share precise inputs and export full results.
- Discrete Fourier Transform Calculator Compute DFT, inverse DFT, FFT and IFFT for real or complex sequences up to 64 samples. Compare all bins, inspect magnitudes, share inputs and export results.
- Division Calculator Divide numbers with quotient, remainder, and decimal results for quick arithmetic checks. Runs locally in your browser. Free online tool — no sign-up.
- Dodecahedron Calculator Calculate measures for a dodecahedron with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Dot Product Calculator Calculate vector dot products in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Ellipse Calculator Calculate ellipse area, foci, eccentricity and approximate perimeter from two semiaxes. Inspect formulas, numerical limits, figures and complete result exports.
- Ellipsoid Calculator Calculate measures for an ellipsoid with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Error Function Calculator Calculate erf(x) and the complementary error function erfc(x). Explore a live graph, worked examples, input limits and shareable results computed locally.
- Euler Form Calculator Convert rectangular or polar complex numbers into Euler form with angles in degrees. Explore the Argand diagram, worked examples and numerical limits.
- Euler Method Calculator Forward Euler for a scalar first-order IVP y′=f(t,y). Same engine as Ordinary Differential Equation. Not RK4, not rk45, not a system. Runs locally.
- Exponent Calculator Calculate real powers, solve for a base or exponent, and keep both real roots when needed. Check domain limits, view graphs, share results, and export data.
- Exponential Growth Calculator Calculate exponential growth or decay with periodic or continuous models. Solve value, time, initial amount, or rate, and compare all four inputs online.
- Factorial Calculator Calculate factorials from 0! to 5000! locally. See digit counts and product steps, share inputs, and export every digit with versioned JSON or CSV results.
- FFT Calculator Compute radix-2 FFT for real or complex sequences with power-of-two lengths up to 64. Inspect all frequency bins, share inputs and export complete results.
- Fibonacci Calculator Calculate exact Fibonacci numbers from F₀ = 0 and F₁ = 1 through index 1000. View the preceding term, partial sum, worked steps and complete integer exports.
- Fractions Calculator Add, subtract, multiply and divide fractions or mixed numbers. Simplify, convert decimals, follow exact steps, and share or export complete versioned results.
- Frustum Calculator Calculate measures for a conical frustum with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Gamma Function Calculator Calculate Gamma values for real inputs away from its poles. Explore a live graph, worked examples, input limits and shareable results computed locally.
- Gauss Quadrature Calculator n-point Gauss–Legendre quadrature of a polynomial, sin, or exp on [a, b]. Same engine as Definite Integral. Not indefinite CAS. Runs locally.
- GCF Calculator Find the GCF, GCD, or HCF of two or more integers, including exact 48-digit values. See Euclidean steps, factor checks, and complete exports. Free, no sign-up.
- Geometric Sequence Calculator Find exact integer geometric sequence terms and finite sums, including zero, one and negative ratios. Check input limits, worked steps and complete exports.
- Golden Section Search Calculator Golden-section search for a minimum of a polynomial, sin, or exp on [a, b]. Same engine as One-Dimensional Optimization. Not Brent, not multivariate. Runs locally.
- Hyperbola Calculator Calculate hyperbola foci, eccentricity and asymptote slopes from positive semiaxes. Choose orientation, inspect numerical limits and export complete results.
- Icosahedron Calculator Calculate measures for an icosahedron with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Incomplete Beta Calculator Calculate incomplete beta Bx(a,b) and regularized Ix(a,b). Explore a live graph, worked examples, input limits and shareable results computed locally.
- Inverse DFT Calculator Compute the inverse DFT with 1/N normalization for real or complex sequences up to 64 samples. Inspect all samples, share inputs and export complete results.
- Inverse FFT Calculator Compute radix-2 inverse FFT with 1/N normalization for sequences of 1–64 samples at power-of-two lengths. Inspect samples, share inputs and export all results.
- Inverse Laplace Calculator Evaluate inverse Laplace table pairs at nonnegative time. Check formulas, causal limits, numerical warnings, graphs and reproducible share links.
- Inverse Z Calculator Evaluate causal inverse Z-transform table pairs at integer sample indices. Check formulas, ROC, numerical warnings, stem plots and reproducible share links.
- Irregular Polygon Calculator Calculate irregular polygon area and perimeter with full results, clear input limits, shareable links and CSV export. Runs locally in your browser.
- Lambert W Calculator Calculate the principal real Lambert W branch W0(x). Explore a live graph, worked examples, input limits and shareable results computed locally.
- Lambert W₋₁ Calculator Calculate the secondary real Lambert W branch W-1(x). Explore a live graph, worked examples, input limits and shareable results computed locally.
- Laplace Transform Calculator Evaluate eight causal Laplace pairs or their inverse with real inputs. See formulas, ROC limits, numerical warnings, graphs and shareable results.
- LCM Calculator Find the LCM or LCD of two or more integers, including exact 48-digit inputs. Compare methods, read full working, and share or export results. Free, no sign-up.
- Least Squares Calculator Linear least squares for a small real matrix, square or rectangular. Full column rank uses QR; otherwise SVD. Same engine as Linear System. Not Statistics regression. Runs locally.
- Left Nullspace Calculator Left-nullspace (cokernel) of a small real square matrix as ker(Aᵀ). Same engine as Linear System. Trivial left kernel is {0}. Not Jordan form. Runs locally.
- Line Equation Calculator Find the line through two points, including vertical lines. Read slope and standard forms, inspect numeric limits, and share or export coordinate results.
- Line Intersection Calculator Intersect two infinite planar lines defined by points. Distinguish unique, parallel and coincident results; inspect numerical limits, figures and full exports.
- Linear Equation Calculator Solve linear equations in one variable, including identities and inconsistent cases. Compare coefficient decisions, share inputs, or export the full result.
- Linear Inequality Calculator Solve linear inequalities with strict or inclusive bounds. Reverse the relation for negative coefficients, inspect the number line, and export the solution set.
- Linear System Calculator Solve small linear systems Ax = b, plus det, inverse, rank, LU, Cholesky, QR, SVD, least squares, RREF, condition number, nullspace, column space, rowspace, left-nullspace, and eigenvalues. Same engine as the matrix workspace. Not a CAS. Runs locally.
- Log Calculator Solve logarithms for the result, argument or base. Explore real graphs, view calculation steps, and share or export complete results for REST and MCP use.
- LU Factorization Calculator Doolittle LU factorization with partial pivoting for a small real matrix. Same engine as Linear System. Not a CAS. Runs locally.
- Matrix Determinant Calculator Determinant of a small real matrix. Same engine as Linear System and the matrix workspace. Not a CAS. Runs locally.
- Matrix Eigenvalues Calculator Eigenvalues and eigenvectors of a small real matrix via the characteristic polynomial. Same engine as Linear System. Not a CAS. Runs locally.
- Matrix Inverse Calculator Inverse of a small real matrix via Gauss–Jordan. Same engine as Linear System. Singular matrices fail. Not a CAS. Runs locally.
- Matrix Rank Calculator Rank of a small real matrix via Gaussian elimination. Same engine as Linear System. Not a CAS. Runs locally.
- Modular Inverse Calculator Find exact modular inverses for coprime signed integers up to 48 digits. Check the original Bézout identity, reject invalid inputs, and export complete results.
- Modulo Calculator Find exact Euclidean quotients and remainders for signed integers up to 48 digits. Check identities, calculate modular inverses, and share complete results.
- Multiplication Calculator Multiply two numbers instantly, or see long multiplication with partial products, carrying, decimals, and sign rules. Runs locally in your browser.
- Natural Log (ln) Calculator Calculate ln(x) for positive numbers with steps, a live graph and an exponential reverse check. Share results or export full precision for REST and MCP use.
- Nonlinear Equation Calculator Solve a polynomial or sin x for one approximate real zero using Newton, bisection, or secant. Inspect the residual and stopping reason. Calculate locally.
- Normalized Sinc Calculator Calculate normalized sinc(x) = sin(πx)/(πx), with sinc(0)=1. Explore a live graph, worked examples, input limits and shareable results computed locally.
- Nullspace Calculator Right nullspace of a small real square matrix from RREF. Same engine as Linear System. Trivial kernel is {0}. Left-nullspace is a sibling. Runs locally.
- Numerical Derivative Calculator Finite-difference derivative of a polynomial, sin, or exp, plus a numeric two-sided limit. Central, forward, backward, or limit. Discovery /two-sided-limit. Not symbolic d/dx. Runs locally.
- Numerical Interpolation Calculator Piecewise-linear, Lagrange, or natural cubic spline of tabulated (x, y). Not regression, not CAS. Runs locally.
- Numerical Root Calculator Find one approximate real zero of a polynomial or sin x using Newton, bisection, or secant. Inspect the residual and stopping reason. Calculate locally.
- Octahedron Calculator Calculate measures for an octahedron with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- One-Dimensional Optimization Calculator Minimize a polynomial, sin, or exp on [a, b] by golden-section search or Brent. Not multivariate, not max, not CAS. Runs locally.
- Ordinary Differential Equation Calculator Scalar first-order IVP y′=f(t,y) by Euler or classical RK4. rhs linear is y′=k y; poly is y′=p(t). Not rk45, not systems, not PDE, not CAS. Runs locally.
- Parabola Calculator Find the focus, directrix and equation of a horizontal or vertical parabola from its signed focal parameter. Explore figures, limits and full result exports.
- Parallelogram Calculator Calculate parallelogram area and perimeter with full results, clear input limits, shareable links and CSV export. Runs locally in your browser.
- Percent Error Calculator Calculate absolute or signed percent error, solve for observed or accepted values, and inspect every inverse branch, numerical limit, formula and export.
- Percentage Calculator Calculate percentages, percentage of a number, and “what percent is X of Y” with clear arithmetic steps. Runs locally in your browser. Try it free.
- Percentage Change Calculator Calculate percentage increase or decrease and reverse-solve initial or final values. See complete signed solutions, formulas, and numerical limits.
- Permutation Combination Calculator Calculate exact permutations and combinations for 0 ≤ k ≤ n ≤ 1000. Compare ordered and unordered selections, share inputs, and export the complete count.
- Plane Geometry Calculator Calculate plane shape area and perimeter with full results, clear input limits, shareable links and CSV export. Runs locally in your browser.
- Point Line Distance Calculator Find the distance and perpendicular foot from a point to a two-point line. Inspect formulas, numeric limits and a figure, then share or export complete results.
- Polynomial Evaluate Calculator Evaluate real polynomials of degree 1–8 with exact rational Horner arithmetic and one binary64 rounding. Inspect numerical limits, share inputs, and export.
- Polynomial Roots Calculator Find all roots of real polynomials of degree 1–8, including complex and repeated roots. Check numerical limits, share inputs, and export complete results.
- Prime Factorization Calculator Find exact prime factors and test primality for integers from 1 to 10^12. Check exponents, view complete factorization steps, and export or share results.
- Prism Calculator Calculate measures for a rectangular prism with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Proportion Calculator Solve a proportion for one missing term using exact rational arithmetic. Enter integers, decimals or fractions; check nonzero denominators and worked steps.
- Pyramid Calculator Calculate measures for a centered pyramid with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Pythagorean Theorem Calculator Solve a right triangle with a² + b² = c². Enter any two of legs a, b and hypotenuse c to find the third side, plus area and perimeter. Try it free.
- QR Factorization Calculator Householder QR factorization of a small real matrix, square or rectangular. Same engine as Linear System. Not a CAS. Runs locally.
- Quadratic Formula Calculator Solve real quadratic equations with two, repeated, or complex roots. Inspect the discriminant, vertex, numerical limits, worked steps, and complete exports.
- Quadratic Inequality Calculator Find solution intervals for real quadratic inequalities. Choose strict or inclusive endpoints, inspect numerical limits, share raw inputs, and export results.
- Ratio Calculator Simplify, scale, split and compare exact ratios, solve proportions, and convert parts to percentages. See formulas, input limits, worked steps and exports.
- Rational Equation Calculator Solve rational equations in one variable while excluding denominator poles. Inspect identities, empty sets, and valid roots, then share or export full results.
- Rational Inequality Calculator Solve rational inequalities with exact coefficient decisions and excluded poles. Inspect open or closed solution intervals, share inputs, and export the set.
- Rectangle Calculator Calculate rectangle area and perimeter with complete numerical results, clear input limits, shareable links and CSV export. Runs locally in your browser.
- Regular Frustum Calculator Calculate measures for an n-gon frustum with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Regular Polygon Calculator Calculate regular polygon area and perimeter with full results, clear input limits, shareable links and CSV export. Runs locally in your browser.
- Regular Prism Calculator Calculate measures for an n-gon prism with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Regular Pyramid Calculator Calculate measures for an n-gon pyramid with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Root Calculator Calculate square, cube, and nth real roots with a live graph. Check negative radicands and index limits, then share inputs or export full precision results.
- Row Space Calculator Row space of a small real square matrix from nonzero RREF rows. Same engine as Linear System. Trivial rowspace is {0}. Left-nullspace is a sibling. Runs locally.
- RREF Calculator Gauss–Jordan reduced row echelon form for a small real square matrix. Same engine as Linear System. Not a CAS. Runs locally.
- Runge–Kutta Calculator Classical fourth-order Runge–Kutta for a scalar first-order IVP y′=f(t,y). Same engine as Ordinary Differential Equation. Not Euler, not rk45, not a system. Runs locally.
- Scalar Triple Product Calculator Calculate scalar triple products in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Scientific Notation Calculator Convert decimal, scientific, E and engineering notation; normalize coefficients and calculate with powers of ten. See steps, limits and shareable results.
- Sector Calculator Calculate sector area and arc length from radius and an angle in degrees. Explore formulas, worked examples, units, and trusted mathematical references.
- Sequence Calculator Calculate exact integer terms and sums for arithmetic, geometric, Fibonacci and linear recurrence sequences. Check indices, limits, examples and full exports.
- Simpson Rule Calculator Composite Simpson 1/3 of a polynomial, sin, or exp on [a, b]. Same engine as Definite Integral. Not indefinite CAS. Runs locally.
- Sin Calculator Calculate sine in degrees or radians, or from opposite and hypotenuse lengths. Preserve tiny results, inspect limits and worked steps, and export full inputs.
- Sinc Function Calculator Calculate unnormalized sinc(x) = sin(x)/x, with sinc(0)=1. Explore a live graph, worked examples, input limits and shareable results computed locally.
- Solid Geometry Calculator Calculate measures for 20 solid models with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Special Functions Calculator Evaluate erf, Gamma, Bessel, Lambert W, beta and sinc. Explore a live graph, worked examples, input limits and shareable results computed locally.
- Sphere Calculator Calculate measures for a sphere with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Spherical Cap Calculator Calculate measures for a spherical cap with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Spherical Lune Calculator Calculate measures for a spherical lune with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Spherical Sector Calculator Calculate measures for a spherical sector with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Spherical Wedge Calculator Calculate measures for a spherical wedge with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Spherical Zone Calculator Calculate measures for a spherical zone with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Spline Interpolation Calculator Natural cubic spline through tabulated (x, y). Same engine as Numerical Interpolation. Not Akima, PCHIP, or regression. Runs locally.
- Square Calculator Calculate square area and perimeter with complete numerical results, clear input limits, shareable links and CSV export. Runs locally in your browser.
- Square Root Calculator Find principal real or imaginary square roots with worked steps and a live graph. Share inputs, export complete results, or use the REST and MCP interfaces.
- Subtraction Calculator Solve a missing subtraction term or see exact decimal long subtraction with borrowing. Compare modes, check input limits, and share or export complete results.
- Sum Calculator Add decimal lists exactly, find totals and means, or check long addition with carry steps. Supports negatives, scientific notation, and shareable results.
- SVD Calculator Singular value decomposition of a small real matrix, square or rectangular. Same engine as Linear System. Least squares is a sibling discovery URL. Not a CAS. Runs locally.
- Tan Calculator Calculate tangent in degrees or radians with stable angle reduction, clear pole errors, near-singularity warnings, full-precision exports and shareable results.
- Tetrahedron Calculator Calculate measures for a tetrahedron with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Torus Calculator Calculate measures for a ring torus with consistent units. See formulas, numerical limits and a section diagram, then share or export complete results.
- Trapezoid Calculator Calculate trapezoid area and perimeter with complete numerical results, clear input limits, shareable links and CSV export. Runs locally in your browser.
- Trapezoidal Rule Calculator Composite trapezoidal rule of a polynomial, sin, or exp on [a, b]. Same engine as Definite Integral. Not the fluid trapezoid pages. Runs locally.
- Triangle Solver Solve triangle sides, angles, area and perimeter with SSS, SAS, ASA, AAS or SSA. Inspect every solution, numerical limits and complete shareable result exports.
- Two-Sided Limit Calculator Numeric two-sided limit of a polynomial, sin, or exp at a finite x. Same engine as Numerical Derivative. Not one-sided. Not L’Hôpital. Not a second engine. Runs locally.
- Vector Add Calculator Calculate vector addition in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Vector Angle Calculator Calculate the included vector angle in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Vector Calculator Calculate nine vector operations in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Vector Magnitude Calculator Calculate vector magnitude in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Vector Normalize Calculator Calculate unit vectors in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Vector Projection Calculator Calculate vector projections in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Vector Subtract Calculator Calculate vector subtraction in 2D or 3D. Explore worked steps, numerical limits and verified results. Share inputs or export the complete calculation.
- Z Transform Calculator Evaluate eight causal Z-transform pairs or inverse sequences. Check real inputs, ROC limits, formulas, numerical warnings, graphs and shareable results.
Wire calculators
Wire gauge, AWG/SWG, and voltage drop.
- AWG to mm Calculator Convert American Wire Gauge (AWG) to conductor diameter in mm and cross-section in mm² with standard AWG tables. Runs locally in your browser.
- SWG to mm Calculator Convert Standard Wire Gauge (SWG) to millimetres and mm² for British/imperial wire sizing. Runs locally in your browser. Free online tool — no sign-up.
- Voltage Drop Calculator Estimate DC or resistive single-phase / balanced three-phase voltage drop and conductor I²R loss from current, cable length, and Ω/km. Optional system voltage shows % drop and load voltage. Runs locally in your browser. Try it free.
- Wire Gauge Chart Look up AWG wire gauge charts for diameter, area, and typical ampacity reference values in one place. Runs locally in your browser. Try it free.
Electrical calculators
Amps, volts, watts, kVA, and power tools.
- 555 Timer Calculator Astable frequency, period, high/low times and duty — or monostable pulse width — for the classic 555 timer from R and C. ln(2)-canonical NE555 timing with device-applicability warnings.
- AC to DC Rectifier Calculator Ideal half-wave/full-wave rectified waveform — peak, average and RMS voltage, with optional capacitor ripple estimation. Runs locally in your browser.
- ADC Error Budget Calculator Combine ADC gain, offset, INL, and DNL errors (RSS or worst-case) into total LSB, volts, and %FS. Runs locally in your browser.
- ADC SNR / Quantization Calculator Ideal quantization SNR ≈ 6.02·N + 1.76 dB for a full-scale sine; reverse measured SINAD to ENOB. Runs locally in your browser.
- Amps to kW Calculator Convert amps and volts to real power in kW for DC, AC single-phase, and balanced AC three-phase line-to-line. Runs locally in your browser. Free online tool — no sign-up.
- Amps to VA Calculator Convert amps and volts to apparent power in VA or kVA for single-phase and three-phase circuits. Also convert VA back to amps. Fast and free.
- Amps to Volts Calculator Solve voltage from current and resistance or power using Ohm’s law and P = V × I. Supports resistive DC and RMS AC estimates with clear formulas.
- Antenna Length Calculator Compute dipole (λ/2) or monopole (λ/4) antenna length from frequency and an empirical length factor. Runs locally in your browser.
- Battery Pack Sizing Calculator Size battery capacity (Ah) from load and runtime targets, with optional series/parallel cell geometry. Inverse of Battery Runtime (watts load-side / amps battery-side).
- Battery Runtime Calculator Estimate battery runtime from capacity (Ah or mAh), voltage, and constant load in watts (load-side) or amps (battery-side), with planning DoD and load-side efficiency. Runs locally in your browser.
- Battery Runtime with Temperature Estimate constant-load battery runtime with a generic cold-derating heuristic about 25 °C. Extends Battery Runtime (watts load-side / amps battery-side). Planning model — not chemistry.
- Buck Converter Ripple Calculator Assumed-CCM buck peak-to-peak inductor ripple ΔI_L,pp = Vout(1−D)/(f L) and optional capacitor-only ΔV_C,pp ≈ ΔI/(8fC). Runs locally in your browser.
- Capacitance Calculator Compute parallel-plate capacitance C=εA/d or combine series/parallel capacitors. Runs locally in your browser.
- Cascaded Noise Figure Calculator Compute cascaded noise figure and total gain for a multi-stage RF chain using the Friis formula. Add, remove, or reorder stages. Runs locally in your browser.
- Coax Impedance Calculator Compute coaxial characteristic impedance Z0 from shield inner diameter D, center-conductor diameter d, and dielectric εr. Ideal TEM, μr≈1. Runs locally in your browser.
- Current Divider Calculator Split a total current between two parallel resistors: I1 = It·R2/(R1+R2), I2 = It·R1/(R1+R2). Runs locally in your browser.
- dBm to Watts Calculator Convert dBm ↔ watts and dBm ↔ milliwatts with hard validation. Canonical Unit Engine for RF power.
- Diode Equation Calculator Shockley diode law I_D=I_S·(e^(V_D/(n·V_T))−1). Solve current or voltage, including reverse branch I_D > −I_S. Runs locally in your browser.
- Electric Power Calculator Calculate electrical power in watts from voltage and current for DC, single-phase AC, or balanced three-phase AC, from current and resistance, or from energy over time.
- Electricity Bill Calculator Estimate an electricity bill from kWh usage or meter readings, with rate, standing charge, and days of service. Runs locally in your browser.
- Energy Consumption Calculator Estimate energy use in kWh from device watts and hours of operation. Useful for appliance and load planning. Runs locally in your browser. Try it free.
- Energy Cost Calculator Estimate electricity usage cost from watts/hours or kWh and your unit rate. Supports custom billing periods; standing charges and taxes are excluded. Runs locally in your browser.
- eV to Volts Calculator Relate electronvolt energy to electric potential difference through ΔE = qΔV. eV and volts measure different physical quantities. Runs locally in your browser.
- Free-Space Path Loss Calculator Compute free-space path loss FSPL = 20·log10(d·f) + 20·log10(4π/c) from distance and frequency, with optional antenna gains. Runs locally in your browser.
- Heatsink Thermal Resistance Calculator — θJC, θCS, θSA & Junction Temperature Size required heatsink θSA from Tj,max, or compute junction temperature from effective θJA or the θJC+θCS+θSA stack. Device dissipation only. Runs locally in your browser.
- High-Pass Filter Calculator First-order RC high-pass cutoff fc=1/(2πRC) and optional |H(f)|. Twin of the LPF calculator.
- Kirchhoff's Law Calculator Apply Kirchhoff’s voltage law to a series loop or current law to a parallel node with N resistors.
- kVA to Amps Calculator Convert kVA and voltage to line current for single-phase and three-phase systems. Uses √3 for three-phase line-to-line volts. Runs locally in your browser.
- kVA to kW Calculator Convert apparent power (kVA) to real power (kW) with power factor. States when PF is required and when loads are assumed balanced. Try it free.
- kW to VA Calculator Convert kilowatts to volt-amperes using power factor. Distinguishes real vs apparent power for feeder and transformer sizing. Runs locally in your browser.
- kWh to kW Calculator Convert kilowatt-hours and duration into average kilowatts. Clarifies energy vs power for metering and solar sizing. Runs locally in your browser.
- kWh to Watts Calculator Convert energy in kWh and a time period into average power in watts (and reverse) for load and generation estimates. Runs locally in your browser.
- L-section LC Match Calculator Narrowband real RL→Z0 L-section match with dual LP/HP solutions. Runs locally in your browser.
- LDO Thermal Calculator Compute LDO dissipation P=(Vin−Vout)·Iout (+ Iq·Vin) and junction temperature. Runs locally in your browser.
- LED Resistor Calculator Size the series resistor for one or more LEDs: R = (Vs − n·Vf) / If.
- Linear Battery Aging Calculator Estimate battery capacity with a simple linear cycle + calendar aging model: SOH = max(0, 1 − k_cycle·N − k_cal·t), C = C0·SOH. Default coefficients are illustrative. Runs locally in your browser.
- Logic Gate Calculator Evaluate basic digital logic gates from binary inputs. Runs locally in your browser.
- Low-Pass Filter Calculator Design a first-order RC low-pass filter: solve any two of R, C, and cutoff fc = 1/(2πRC), and evaluate magnitude |H(f)| in linear and dB. Runs locally in your browser.
- mAh to Wh Calculator Convert battery capacity from mAh to Wh (and reverse) using nominal voltage—common for USB power banks and Li-ion packs. Runs locally in your browser.
- Microstrip Impedance Calculator Compute microstrip characteristic impedance Z0 from W/H/εr, or synthesize width for a target Z0 (zero-thickness IPC-2141 / Wadell–Hammerstad). Runs locally in your browser.
- MOSFET Conduction Loss Calculator Calculate MOSFET conduction loss from I, Rds(on), current definition (DC / on-interval RMS / full-cycle RMS), and optional Rds(Tj) via linear α or datasheet ratio. Runs locally in your browser.
- MOSFET Junction Temperature Calculator Estimate MOSFET junction temperature from ambient, dissipation, and thermal resistance (effective RθJA, or case/heatsink-dominant RθJC+RθCA). Optional thermal margin.
- MOSFET Switching Loss Calculator First-order hard-switching overlap loss P_sw = ½·Vds·Id·(tr+tf)·f_sw, plus optional gate-drive power Qg·Vdrive·f. Not a full MOSFET loss stack. Runs locally in your browser.
- MOSFET Threshold & Overdrive Calculator Calculate MOSFET overdrive Vod=Vgs−Vth, square-law drain current, or model Vth. Vth here is the long-channel square-law parameter — not datasheet VGS(th). Runs locally in your browser.
- MOSFET Total Loss Calculator MOSFET device dissipation from conduction + hard-switching + optional Coss/Eoss, plus optional gate-drive and Qrr commutation. Tj uses P_device, not associated total. Omitted terms are not treated as 0 W. Runs locally in your browser.
- Ohm's Law Calculator Enter any two of voltage, current, resistance, and power to solve the remaining values. Runs locally in your browser. Free online tool — no sign-up.
- Op-amp Error Budget Calculator Estimate DC output-referred error from Vos, Ib, Ios and feedback resistors (RSS or worst-case).
- Op-Amp Gain Calculator Closed-loop gain for non-inverting (1+Rf/Rg) and inverting (−Rf/Rg) op-amp circuits. Runs locally in your browser.
- Op-amp Noise Calculator Estimate flat-band output noise from en, optional in, gain, and bandwidth. Runs locally in your browser.
- Parallel Resistor Calculator Compute equivalent resistance of two or more resistors in parallel. Runs locally in your browser.
- PCB Differential Impedance Calculator Estimate edge-coupled microstrip differential impedance Zdiff from W, H, S, and εr. Hammerstad/Wadell Z0 plus IPC-2141A-style coupling. Runs locally in your browser.
- PCB Trace Thermal Calculator Estimate copper trace I²R power and temperature rise with a board thermal resistance. Runs locally in your browser.
- PCB Trace Width Calculator (IPC-2221) Size PCB copper traces from current and temperature rise using the classic IPC-2221 I = k·ΔT^0.44·A^0.725 relation for external and internal layers. Runs locally in your browser.
- Power Factor Calculator Calculate power factor from real power, voltage, and current for single-phase and three-phase (line-line or line-neutral) circuits. Try it free.
- RC Time Constant Calculator Calculate the RC time constant τ = R×C, solve for R or C, and get −3 dB frequency plus 2.2τ / 5τ timing estimates. Runs locally in your browser.
- Receiver Sensitivity Calculator Estimate MDS: S = −174 + NF + 10·log10(BW) + SNR_min (dBm). Runs locally in your browser.
- Rectifier Ripple Capacitor Calculator Size filter capacitance or estimate ripple for half/full-wave rectifiers: Vripple ≈ I/(f·C). Runs locally in your browser.
- Reflection Coefficient to Impedance Calculator Convert complex Γ ↔ normalized z (Cartesian or polar Γ). Reports VSWR and return loss. Runs locally in your browser.
- Resistor Color Code Calculator IEC 60062 band colors → Ω ±tol. Runs locally in your browser.
- RF Link Budget Calculator Compute RF link budget: FSPL, path loss with antenna gains and misc loss, received power, and optional margin above sensitivity. Extends Free-Space Path Loss.
- RLC Resonance Calculator Calculate RLC resonant frequency f₀, Q factor, bandwidth, and reactance at resonance for series or parallel circuits from L, C, and R. Runs locally in your browser.
- Series Capacitor Calculator Combine capacitors in series: 1/C = Σ 1/Ci. Runs locally in your browser.
- Skin Depth Calculator Compute electromagnetic skin depth δ = √(ρ/(π·f·μ)) for conductors. Runs locally in your browser.
- Smith Chart Calculator Interactive impedance Smith chart with auto-match, drag-to-tune, L·C·R / T-line / stub / transformer / ‖RLC, Custom Z(f), f-locus, and Touchstone S11/S21 with stability overlays. Runs locally in your browser.
- Stripline Impedance Calculator Estimate symmetric stripline characteristic impedance from W, b, and εr. Extends microstrip / Zdiff. Runs locally in your browser.
- Transformer Sizing Calculator Ideal transformer: Vp/Vs=Np/Ns, currents, and VA = V·I. First-pass sizing. Runs locally in your browser.
- VA to kVA Calculator Convert volt-amperes (VA) to kilovolt-amperes (kVA) with the exact 1000× scale factor used on nameplates. Runs locally in your browser. Try it free.
- Via Current Capacity Calculator Estimate PCB via ampacity from drill diameter, plating thickness, and temperature rise using the IPC-2221 I = k·ΔT^0.44·A^0.725 relation on the plating cross-section.
- Voltage Divider Calculator Solve a two-resistor voltage divider: enter exactly three of Vin, R1, R2, and Vout to find the fourth. Also reports current, power, ratio, and Rth. Try it free.
- Volts to Joules Calculator Relate voltage, charge, or capacitance to energy in joules for electrostatic and capacitor examples. Runs locally in your browser. Try it free.
- Volts to kW Calculator Estimate kilowatts from voltage, current, and power factor for single-phase and three-phase circuits. Runs locally in your browser. Try it free.
- VSWR Calculator Convert between reflection coefficient |Γ|, VSWR, and return loss. Runs locally in your browser.
- Watts to Amps Calculator Convert watts to amps (and reverse) for DC, single-phase, and three-phase circuits. Power factor and voltage inputs included for AC loads. Try it free.
- Watts to Joules Calculator Convert watts and time to energy in joules (and reverse). Shows W × s = J with worked timing examples. Runs locally in your browser. Try it free.
- Watts to kVA Calculator Convert watts to kVA with power factor. Helps size generators and UPS equipment from real power demand. Runs locally in your browser. Try it free.
- Watts to VA Calculator Convert real power in watts to apparent power in VA using power factor. Clarifies W vs VA for sizing breakers and transformers. Try it free.
- Watts to Volts Calculator Find voltage from power and current (or resistance). Useful for DC and resistive AC checks with unit guidance. Runs locally in your browser.
- Watts Volts Amps Calculator Solve any two of watts, volts, amps, and ohms for the other values—an Ohm’s-law style watt–volt–amp workspace. Runs locally in your browser.
- Wavelength Calculator Compute λ = c·VF/f in vacuum or dielectric. Solve for wavelength or frequency. Runs locally in your browser.
- Wheatstone Bridge Calculator Compute Wheatstone bridge output voltage and balance from Vin and four resistors. Runs locally in your browser.
Physics calculators
Kinematics, energy, fluids, thermodynamics, waves, and optics.
- Acceleration Calculator Solve constant acceleration a=(v−u)/t. Runs locally in your browser.
- Alternate Depth Calculator Compute both rectangular depths at the same specific energy from E, Q, and width b. Runs locally. Not specific energy from y+v; not specific force M; not hydraulic jump y2; not critical depth yc as the product.
- Bernoulli Equation Calculator Incompressible Bernoulli along a streamline: solve P2, v2, or h2. Runs locally in your browser.
- Binary to Hex Converter Convert unsigned integers between binary and hexadecimal. Runs locally in your browser.
- Boyle's Law Calculator P₁V₁ = P₂V₂. Runs locally in your browser.
- Broad-Crested Weir Calculator Compute rectangular broad-crested weir discharge Q = C_d (2/3)^{3/2} b √g H^{3/2}. Default C_d=0.85. Runs locally. Not a thin-plate weir, not Manning, not Q=Av, and not an orifice.
- Cavitation Number Calculator Compute the cavitation number σ = (p − p_v) / (½ ρ v²). Runs locally. Not NPSH, not Thoma NPSH/H, not Weber, and not Euler Eu=Δp/(ρ v²).
- Celsius to Kelvin Converter Convert between Celsius and Kelvin with hard absolute-zero checks. Runs locally in your browser.
- Centripetal Force Calculator F = m v² / r. Runs locally in your browser.
- Charles's Law Calculator V₁/T₁ = V₂/T₂. Runs locally in your browser.
- Chezy Formula Calculator Compute open-channel mean velocity V = C √(R S). Runs locally. Not Manning n, not Q=Av, not Hazen–Williams, and not Darcy.
- Colebrook Friction Factor Calculator Solve the Colebrook–White equation for Darcy friction factor f from Re and ε/D. Turbulent pipes Re≥4000. Runs locally. Not laminar 64/Re and not a Moody-chart lookup.
- Composite Wall Calculator Compute plane composite-wall resistance from a layer list. R_i = L_i/(k_i A), optional films 1/(h A), R = R_in + ΣR_i + R_out. Optional Q=ΔT/R. Runs locally. Not Fourier/Newton Q, not a lumped R-network, and not heatsink θ.
- Concentric Reducer Calculator Compute concentric-reducer loss h = K v₂² / (2g) with K = 0.5 (1 − A₂/A₁) referenced to the downstream speed. Runs locally. Not sudden expansion, not gradual contraction α, not vena-contracta C_c, not catalog K, and not Q=Av.
- Coulomb's Law Calculator Compute electrostatic force F = k·|q1·q2|/r² between point charges. Runs locally in your browser.
- Critical Depth Calculator Compute rectangular critical depth yc = (q²/g)^{1/3}. Runs locally. Not a Froude wrap, not specific energy, not a hydraulic jump, and not Q=Av.
- Critical Slope Calculator Compute rectangular critical bed slope Sc such that yn=yc using SI Manning at y=yc. Runs locally. Not Manning A,R; not normal-depth yn; not critical-depth yc as the product; not Chezy; not Q=Av.
- Cutthroat Flume Calculator Compute Skogerboe cutthroat flume free-flow discharge from throat width W, independent flume length L_f, and gage head Ha. Runs locally. Not a Parshall flume, not a thin-plate weir, not a broad-crested weir, not Manning, not Q=Av, and not an orifice.
- Darcy–Weisbach Calculator Compute pipe head loss hf = f L v²/(2 g D) and Δp = ρ g hf from a given Darcy friction factor. Runs locally. Does not solve Colebrook for f.
- Displacement Calculator Δx = x − x₀. Runs locally in your browser.
- Doppler Effect Calculator f' = f (v±vo)/(v±vs). Runs locally in your browser.
- Drag Force Calculator Fd = ½ ρ v² Cd A. Runs locally in your browser.
- Drowned Sluice Calculator Compute Swamee 1992 drowned undershot sluice discharge from opening a, width b, upstream depth y1, and downstream depth y2. Runs locally. C_d is reported, not an input. Not free-flow sluice, not a Villemonte weir, not a tank orifice, not Manning, and not Q=Av.
- Efficiency Calculator Power efficiency η=Pout/Pin as fraction and percent. Runs locally in your browser.
- Elbow Flow Meter Calculator Compute 90° elbow-tap discharge from inner/outer Δp. C=√((R/D)/2). Runs locally. Not pipe-bend K, not Pitot C=1, not venturi, not ISO 5167-6 wedge, not given C_d.
- Electric Field Calculator E = k|Q|/r². Runs locally in your browser.
- Faraday's Law Calculator ε = N |ΔΦ| / Δt. Runs locally in your browser.
- Flow Rate Calculator Volumetric flow Q=A·v (or from pipe diameter). Runs locally in your browser.
- Force Calculator (F=ma) Solve Newton’s second law for force, mass, or acceleration. Runs locally in your browser.
- Free Fall Calculator Free-fall distance, speed, or time under constant g (optional initial velocity). Runs locally in your browser.
- Friction Calculator F = μ N. Runs locally in your browser.
- Froude Number Calculator Compute the open-channel Froude number Fr = v / √(g L). Default g=9.80665 m/s². Runs locally. Not Reynolds, not Manning, not Chezy, and not Q=Av.
- Gradual Contraction Calculator Compute conical-contraction loss h = K v2² / (2g) with K = 0.5 sin(α) (1 − v1/v2). α is the wall half-angle. Runs locally. Not sudden contraction, not gradual expansion, not minor-loss K as an input, and not Q=Av.
- Gradual Expansion Calculator Compute conical-diffuser loss h = k (v1 − v2)² / (2g) with k = 2.6 sin(α). α is the wall half-angle. Runs locally. Not sudden expansion, not minor-loss K as an input, and not Q=Av.
- Hagen–Poiseuille Calculator Compute laminar circular-pipe flow Q = π Δp D⁴ / (128 μ L). Runs locally. Not Darcy f, not Colebrook, and not Q=Av.
- Half-Life Calculator Radioactive decay with N=N₀·2^(−t/T½). Runs locally in your browser.
- Hazen–Williams Calculator Compute SI Hazen–Williams head loss hf = 10.67 L Q^{1.852} / (C^{1.852} D^{4.87}) for a circular water pipe. Runs locally. Not Darcy–Weisbach, not Colebrook, and not Manning.
- Heat Transfer Calculator Compute conductive Q=kAΔT/L or convective Q=hAΔT heat transfer rate. Runs locally in your browser.
- Hydraulic Diameter Calculator Compute hydraulic diameter D_h=4A/P_w for a general section, a full circular pipe, a closed rectangular duct, or an annulus. Runs locally. Not Q=Av, not Manning, and not Darcy.
- Hydraulic Jump Calculator Compute rectangular sequent depths y₂/y₁ = (√(1+8 Fr₁²) − 1)/2. Fr₁ > 1. Runs locally. Not a Froude wrap, not Manning, not a weir, and not Q=Av.
- Hz to Rad/s Converter Convert between hertz and radians per second with ω = 2πf. Runs locally in your browser.
- Ideal Gas Law Calculator Solve the ideal gas law for P, V, n, or T with SI units. Runs locally in your browser.
- Impulse Calculator J = F Δt = Δp. Runs locally in your browser.
- ISO 5167 Cone Meter Calculator Compute ISO 5167-5 uncalibrated cone-meter discharge. β=√(1−(d_c/D)²). Runs locally. Not ISA 1932, not RHG orifice, not ISO 5167-4 type C, not long-radius, not given C_d.
- ISO 5167 Long-Radius Nozzle Calculator Compute ISO 5167-3 long-radius nozzle discharge with C from β. Runs locally. Not ISA 1932, not given C_d=0.98, not RHG orifice, not ISO 5167-4 type C, not Q=Av.
- ISO 5167 Nozzle Calculator Compute ISO 5167-3 ISA 1932 nozzle discharge with C from β and Re_D, not a given C_d. Runs locally. Not a venturi wrap with C_d=0.98, not orifice C_d=0.61, not Q=Av, and not Darcy.
- ISO 5167 Orifice Plate Calculator Compute ISO 5167-2 orifice-plate discharge with Reader–Harris/Gallagher C from β, Re_D, and tapping. Runs locally. Not tank orifice C_d A √(2gH), not given C_d=0.61, not ISA 1932 nozzle, not venturi C_d=0.98.
- ISO 5167 Venturi Tube Calculator Compute ISO 5167-4 classical Venturi-tube discharge with C from convergent type. Runs locally. Not given C_d=0.98, not ISA 1932 nozzle, not RHG orifice, not Q=Av.
- ISO 5167 Wedge Meter Calculator Compute ISO 5167-6 uncalibrated wedge-meter discharge. β from circular-segment h/D. Runs locally. Not cone C=0.82, not ISA 1932, not RHG orifice, not ISO 5167-4 type C, not given C_d.
- Joule to eV Converter Convert energy between joules and electronvolts (exact SI factor). Runs locally in your browser.
- Kinetic Energy Calculator KE = ½ m v². Runs locally in your browser.
- kWh to Joules Converter Convert energy between kilowatt-hours and joules (1 kWh = 3.6 MJ). Runs locally in your browser.
- Lens Maker Calculator 1/f = (n−1)(1/R1 − 1/R2). Runs locally in your browser.
- Linear Thermal Expansion Calculator Calculate free linear expansion from length, temperature change, and a user-supplied coefficient. Solve ΔL, final length, α, or ΔT without a material database.
- m/s to km/h Converter Convert speed between metres per second and kilometres per hour (×3.6). Runs locally in your browser.
- Magnetic Field Calculator B = μ₀ I / (2π r). Runs locally in your browser.
- Manning Formula Calculator Compute SI Manning discharge Q = (1/n) A R^{2/3} S^{1/2}. Runs locally. Not Q=Av, not Darcy–Weisbach, and not a weir.
- Minor Loss Calculator Compute fitting minor loss h_m = K v²/(2g). Optional Δp = ρ g h_m. Runs locally. Not Darcy–Weisbach, not Hazen–Williams, and not an orifice.
- Mitered Bend Calculator Compute sharp mitered-elbow loss h = K v² / (2g) with K = n [sin²(δ/2) + 2 sin⁴(δ/2)], δ = θ/n. Runs locally. Not circular-arc R/D, not minor-loss K as an input, not Crane f_T, and not Q=Av.
- Momentum Calculator Solve linear momentum p=mv for p, m, or v. Runs locally in your browser.
- Newton to Lbf Converter Convert force between newtons and pound-force (1 lbf = 4.4482216152605 N). Runs locally in your browser.
- Normal Depth Calculator Compute rectangular uniform-flow normal depth yn from SI Manning with A=b yn and R=b yn/(b+2 yn). Runs locally. Not Manning A,R; not critical depth; not specific energy; not Chezy; not Q=Av.
- NPSH Calculator Compute NPSH available from an open tank or a suction flange, and compare with manufacturer NPSHr. Runs locally. Not pump power, not an orifice, not a weir, not Q=Av, and not Darcy.
- Ogee Spillway Calculator Compute USBR high-overflow ogee spillway discharge from crest length L, head H, and design head Hd. Runs locally. C is 3.98 (H/Hd)^{0.12}, not an input. Not a thin-plate weir, not broad-crested, not a sluice, not Manning, and not Q=Av.
- Orifice Discharge Calculator Compute sharp-edged orifice discharge. Tank Q=C_d A √(2gH). Meter Q=C_d E A_t √(2Δp/ρ) with E=1/√(1−β⁴). Runs locally. Not a weir, not Q=Av, not Darcy, and not Manning.
- Parshall Flume Calculator Compute USBR 1–8 ft Parshall flume free-flow discharge from throat width W and gage head Ha. Runs locally. Not a thin-plate weir, not a broad-crested weir, not Manning, not Q=Av, and not an orifice.
- Pipe Bend Calculator Compute circular-arc bend loss h = K v² / (2g) with K = 0.21 (θ/90)/√(R/D). Runs locally. Not minor-loss K as an input, not mitered, not Darcy, and not Q=Av.
- Pipe Cross Calculator Compute equal-area sharp 90° four-way cross loss h = K v_c² / (2g) from dividing or combining flow and branch or through split with equal opposite laterals. Runs locally. Not a 90° tee, not a wye, not catalog K, and not Q=Av.
- Pipe Entrance Calculator Compute pipe-inlet loss h = K v² / (2g) from geometry: flush K=0.5, reentrant K=0.8, rounded K=0.5/[1+36(rᵢ/D)^1.2]. Runs locally. Not catalog K, not circular-arc R/D, not mitered n, and not Q=Av.
- Pipe Exit Calculator Compute pipe-exit loss h = K v² / (2g) with K=1 into a large reservoir. Runs locally. Not catalog K, not inlet geometry, not sudden expansion (v1−v2)², and not Q=Av.
- Pipe Period Calculator Compute the water-hammer pipe period T = 2L/c. Runs locally. Not Joukowsky Δp, not Korteweg–Hall c from K/D/e/E, and not Darcy f.
- Pipe Tee Calculator Compute equal-area sharp 90° T loss h = K v_c² / (2g) from dividing or combining flow and branch or run split. Runs locally. Not catalog K, not a bend, not pipe-entrance, not pipe-exit, and not Q=Av.
- Pipe Wye Calculator Compute equal-area sharp wye loss h = K v_c² / (2g) from branch angle α in (0, 90°), dividing or combining flow, and branch or run split. Runs locally. Not a 90° tee, not catalog K, not a bend, and not Q=Av.
- Pitot Tube Calculator Compute incompressible pitot-static speed v = C √(2 Δp / ρ). Default C=1. Runs locally. Not a venturi, not an orifice, not Q=Av, and not two-station Bernoulli.
- Potential Energy Calculator PE = m g h. Runs locally in your browser.
- Projectile Motion Calculator Compute range, apex height, and flight time for flat-ground projectile motion (no drag). Runs locally in your browser.
- Projectile Trajectory Calculator R = v₀² sin(2θ) / g. Runs locally in your browser.
- PSI to Bar Converter Convert between pound-force per square inch and bar. Runs locally in your browser.
- Pump Power Calculator Compute incompressible pump power P=ρgQH/η and affinity-law scaling Q∝ND, H∝N²D², P∝N³D³. Runs locally. Not an orifice, not a weir, not Q=Av, and not Darcy.
- Reynolds Number Calculator Compute Re = ρvL/μ (or vL/ν) with laminar/turbulent guidance for pipes. Runs locally in your browser.
- Side Weir Calculator Compute Borghei 1999 sharp-crested rectangular side-weir discharge from channel width B, weir length L, upstream depth y1, sill p, and approach Q1. Runs locally. C_d is 0.71−0.41 Fr₁−0.22(p/y1), not an input. Not a frontal thin-plate weir, not an ogee, not a sluice, not Manning, and not Q=Av.
- Sluice Gate Calculator Compute free-flow undershot sluice discharge from gate opening a, width b, and upstream depth y1. Runs locally. C_d is Swamee 1992, not an input. Not a tank orifice, not a weir, not a flume, not Manning, and not Q=Av.
- Snell's Law Calculator n₁ sinθ₁ = n₂ sinθ₂. Runs locally in your browser.
- Sound Level Calculator L = 10 log₁₀(I/I₀). Runs locally in your browser.
- Specific Energy Calculator Compute open-channel specific energy E = y + v²/(2g). Runs locally. Not a Froude wrap, not a hydraulic jump, and not Q=Av.
- Specific Force Calculator Compute rectangular specific force M = Q²/(gA) + A ȳ with ȳ = y/2. Runs locally. Not hydraulic jump y2; not specific energy E; not Froude as the product; not Manning; not Q=Av.
- Specific Heat Capacity Calculator Solve Q = m c ΔT for heat, mass, specific heat, or temperature change. Runs locally in your browser.
- Stefan–Boltzmann Calculator Compute net gray-body flux q = εσ(Th⁴−Tc⁴) and optional Q = A·q. σ from CODATA 2018. Runs locally. Not Fourier/Newton heat-transfer and not a view-factor solver.
- Submerged Weir Calculator Compute Villemonte rectangular submerged-weir discharge from crest L, upstream head H1, and downstream head H2. Qs=Qf [1−(H2/H1)^{1.5}]^{0.385}. Runs locally. Not free-flow thin-plate H only, not an ogee, not a side weir, not Manning, and not Q=Av.
- Sudden Contraction Calculator Compute vena-contracta sudden-contraction loss h = (1/C_c − 1)² v2² / (2g). Default C_c=0.62. Runs locally. Not sudden expansion, not minor-loss K as an input, not an orifice, and not Q=Av.
- Sudden Expansion Calculator Compute Borda–Carnot sudden-expansion loss h = (v1 − v2)² / (2g). Runs locally. Not minor-loss K as an input, not Darcy, not an orifice, and not Q=Av.
- SUVAT Calculator Constant-acceleration kinematics: solve v, s, a, or t (SUVAT). Runs locally in your browser.
- Tesla to Gauss Converter Convert magnetic flux density between tesla and gauss (1 T = 10000 G). Runs locally in your browser.
- Thermal Resistance Calculator Compute lumped thermal resistance. Conduction R=L/(k A), convection R=1/(h A), series ΣR, parallel 1/R=Σ1/R_i. Optional Q=ΔT/R. Runs locally. Not Fourier/Newton Q, not heatsink θ, and not steam.
- Time Dilation Calculator Δt = γ Δτ. Runs locally in your browser.
- Torque Calculator Compute torque τ = r F sinθ. Runs locally in your browser.
- Trapezoidal Alternate Depth Calculator Compute both trapezoid depths at the same specific energy from E, Q, b, and z with A=(b+z y)y. Runs locally. Not rectangular alternate depth; not trapezoid E; not trapezoid yc; not trapezoid yn.
- Trapezoidal Critical Depth Calculator Compute trapezoid critical depth from Q, bottom width b, and side slope z. Runs locally. Not rectangular yc=(q²/g)^{1/3}, not normal depth, and not Q=Av.
- Trapezoidal Hydraulic Jump Calculator Compute trapezoid sequent depths from specific force on A=(b+z y)y. Runs locally. Not rectangular Bélanger y2/y1=(√(1+8Fr₁²)−1)/2; not trapezoid alternate E-pair; not trapezoid yc; not trapezoid yn.
- Trapezoidal Normal Depth Calculator Compute trapezoid uniform-flow yn from SI Manning with A=(b+z y)y and P=b+2 y √(1+z²). Runs locally. Not rectangular yn, not trapezoid yc, not Manning A,R, not Chezy, not Q=Av.
- Trapezoidal Specific Energy Calculator Compute trapezoid specific energy E=y+Q²/(2gA²) with A=(b+z y)y. Runs locally. Not rectangular E=y+v²/(2g), not trapezoid yc, not trapezoid yn, not Manning A,R, not Q=Av.
- Trapezoidal Specific Force Calculator Compute trapezoid specific force M = Q²/(gA) + A ȳ on A=(b+z y)y. Runs locally. Not rectangular ȳ=y/2; not sequent y2; not specific energy E; not Manning; not Q=Av.
- Valve Flow Coefficient Calculator Compute incompressible liquid valve flow from Kv or Cv. Q_m³/h = Kv √(Δp_bar/SG). Kv = 0.865 Cv. Runs locally. Not a venturi, not an orifice, not Q=Av, and not Darcy.
- Velocity Calculator Solve average velocity v=s/t for v, s, or t. Runs locally in your browser.
- Venturi Meter Calculator Compute incompressible venturi flow Q = C_d A2 √(2Δp/(ρ(1−β⁴))) with β = D2/D1. Default C_d = 0.98. Runs locally. Not an orifice plate, not Q=Av, not Darcy, and not valve Cv/Kv.
- Viscosity Calculator τ = η du/dy. Runs locally in your browser.
- Water Hammer Calculator Compute Joukowsky water-hammer Δp = ρ c Δv. Runs locally. Not Darcy f, not minor-loss K, and not Q=Av.
- Watts to Horsepower Converter Convert power between watts and mechanical horsepower (1 hp = 745.6998715822702 W). Runs locally in your browser.
- Wave Celerity Calculator Compute pipe-wave celerity c = √[(K/ρ)/(1+(K D)/(E e))]. Runs locally. Not Joukowsky Δp, not Darcy f, and not minor-loss K.
- Weber Number Calculator Compute the Weber number We = ρ v² L / σ. Runs locally. Not Reynolds, not Froude, not Manning, not Q=Av, and not capillary Ca=μv/σ.
- Weir Discharge Calculator Compute thin-plate weir discharge. Rectangular Q=(2/3) C_d L √(2g) H^{3/2}. V-notch Q=(8/15) C_d √(2g) tan(θ/2) H^{5/2}. Runs locally. Not Manning, not Q=Av, not Darcy, and not an orifice.
- Work and Power Calculator Compute work W=Fs cosθ and power P=W/t or Fv. Runs locally in your browser.
- Young's Modulus Calculator Y = (F/A) / (ΔL/L₀). Runs locally in your browser.
Mechanical calculators
Statics, sections, strength, and beam deflection.
- Angled Pull Calculator Pull at an angle above the horizontal that puts a block on a level surface at impending slip. The normal is W − P sinα. Runs locally.
- Angled Pull on an Incline Calculator The pull at an angle above the horizontal that puts a block on an incline at impending slip. α = 0 is horizontal. α = θ is parallel to the plane. Runs locally.
- Area Moment Calculator Second moment of composite plane areas about the composite centroid. Supply each part's centroidal Ix and Iy. Runs locally. Not a section modulus and not a beam calculator.
- Beam Deflection Calculator Midspan deflection of a simply supported span with one concentrated load. δ = P L³/(48 E I). I is an input. Runs locally.
- Beam Moment Deflection Calculator Midspan deflection of a simply supported span with one end moment. δ = M L²/(16 E I). I is an input. Runs locally.
- Beam Moment Maximum Deflection Calculator Largest deflection of a simply supported span with one end moment. δ = M L²/(9√3 E I) at x = L/√3. I is an input. Runs locally.
- Bending Stress Calculator Elastic bending stress from a moment and a section modulus. S can also be formed from Ix and c. Runs locally.
- Cantilever Deflection Calculator Free-end deflection of a cantilever with one concentrated load at the tip. δ = P L³/(3 E I). I is an input. Runs locally.
- Cantilever Intermediate Deflection Calculator Deflection at a concentrated load on a cantilever. δ = P a³ / (3 E I). a is measured from the fixed end. Runs locally.
- Cantilever Load at a Station Calculator Deflection at station x for a cantilever load at a. x = a is the load page. x = L is the free-end page. Runs locally.
- Cantilever Moment at the Couple Calculator Deflection at a concentrated moment on a cantilever. δ = M a² / (2 E I). a is measured from the fixed end. Runs locally.
- Cantilever Moment Deflection Calculator Free-end deflection of a cantilever with one concentrated moment. δ = M L²/(2 E I). I is an input. Runs locally.
- Cantilever Outer Uniform Calculator Tip deflection when a uniform load starts away from the wall. δ = w [3 L⁴ − a³ (4L − a)] / (24 E I). Runs locally.
- Cantilever Partial Load Calculator Deflection where a uniform load that starts at the wall stops. δ = w a⁴ / (8 E I). Runs locally.
- Cantilever Tip Deflection Calculator Free-end deflection of a cantilever with an intermediate point load. δ = P a² (3L − a) / (6 E I). Runs locally.
- Cantilever Tip-Peak Deflection Calculator Tip deflection of a cantilever whose triangular load peaks at the free end. δ = 11 w0 L⁴ / (120 E I). Runs locally.
- Cantilever Triangular Deflection Calculator Tip deflection of a cantilever whose triangular load peaks at the fixed end. δ = w0 L⁴ / (30 E I). Runs locally.
- Cantilever Uniform Deflection Calculator Free-end deflection of a cantilever with a uniform load. δ = w L⁴/(8 E I). I is an input. Runs locally.
- Cantilever Uniform Load at a Station Calculator Deflection at distance x from the wall. δ = w x² (6 L² − 4 L x + x²) / (24 E I). Runs locally.
- Center-Peaked Triangle at a Station Calculator Deflection at station x when the triangle is 0 at both supports and w0 at midspan. x = L/2 is the midspan page. Runs locally.
- Center-Peaked Triangle Calculator Midspan deflection when a triangular load peaks at midspan. δ = w0 L⁴ / (120 E I). Runs locally.
- Center-Peaked Triangle plus End Moment Calculator Deflection at station x for a center-peaked triangle plus a sagging moment at the right end. x = L/2 is the sum of the two midspan pages. Runs locally.
- Circular Plastic Modulus Calculator Plastic modulus and shape factor of a solid circle. The elastic modulus comes from the circular-section engine. Runs locally.
- Circular Section Calculator Centroidal Ix, Iy, and elastic section moduli of a solid circle from its radius. Runs locally.
- Circular Shear Calculator Neutral-axis shear stress of one solid circle. The area moment comes from the circular-section engine. Runs locally.
- End Moment at a Station Calculator Deflection at station x for one end moment. x is measured from the unloaded end. Runs locally.
- End-Peaked Triangle at a Station Calculator Deflection at station x when the triangle is w0 at both supports and 0 at midspan. x = L/2 is the midspan page. Runs locally.
- End-Peaked Triangle Calculator Midspan deflection when a triangular load peaks at both supports. δ = 3 w0 L⁴ / (640 E I). Runs locally.
- End-Peaked Triangle plus End Moment Calculator Deflection at station x for an end-peaked triangle plus a sagging moment at the right end. x = L/2 is the sum of the two midspan pages. Runs locally.
- Equal End Moments at a Station Calculator Deflection at station x for equal sagging end moments. x = L/2 is the midspan page. Runs locally.
- Equal End Moments Calculator Midspan deflection of a simply supported span with equal sagging end moments. δ = M L² / (8 E I). Runs locally.
- Hollow Circular Plastic Modulus Calculator Plastic modulus of a hollow circle from the outer and inner radii. The elastic modulus comes from the hollow-circular-section engine. Runs locally.
- Hollow Circular Section Calculator Centroidal Ix, Iy, and elastic section moduli of a hollow circle from the outer and inner radii. Runs locally.
- Hollow Circular Shear Calculator Neutral-axis shear stress of one hollow circle. The area moment comes from the hollow-circular-section engine. Runs locally.
- Horizontal Force on an Incline Calculator Horizontal force that puts a block on an incline at impending slip. P is positive toward the uphill side. The normal grows by P sinθ. Runs locally.
- Incline Friction Calculator Force parallel to a rough incline at impending slip. Normal and friction come from the friction engine. Equilibrium is solved with the linear-algebra engine. Runs locally.
- Incline Slip or Tip Calculator Whether a homogeneous rectangle on an incline slips or tips under its own weight. The slip angle is the friction angle. The tip angle is the moment about the downhill edge. Runs locally.
- Inclined-Axis Moment Calculator Centroidal area moments about axes rotated by a given angle. Ix, Iy, and Ixy come from the principal-moment engine. Runs locally. Not the principal values, and not a Mohr circle.
- Ladder Friction Calculator Minimum floor friction for a uniform ladder against a smooth wall. The three reactions are a linear system. μ_min comes from the friction engine. Runs locally.
- Least Pull Calculator The angle and magnitude of the smallest pull that puts a block on a level surface at impending slip. α = arctan μ. Runs locally.
- Least Pull on an Incline Calculator The smallest pull that moves a block up an incline. The pull is at the friction angle above the incline. Runs locally.
- Midspan Load at a Station Calculator Deflection at station x when the load is at midspan. δ = P c (3 L² − 4 c²) / (48 E I). Runs locally.
- Offset Load at a Station Calculator Deflection at station x for one offset load. x = a is the under-load page. x = L/2 is the midspan page. Runs locally.
- Offset Load Deflection Calculator Deflection under a concentrated load that is not at midspan. δ = P a² b² / (3 E I L). I is an input. Runs locally.
- Offset Load Maximum Calculator Largest deflection of a simply supported span with an offset point load. δ = P c (L² − c²)^(3/2) / (9 √3 E I L). Runs locally.
- Offset Load Midspan Calculator Midspan deflection when one concentrated load is not at midspan. δ = P c (3 L² − 4 c²) / (48 E I). Runs locally.
- One-Sided Triangle plus End Moment Calculator Deflection at station x for a one-sided triangle plus a sagging moment at the right end. x = L/2 is the sum of the two midspan pages. Runs locally.
- One-Sided Triangle plus Equal End Moments Calculator Deflection at station x for a one-sided triangle plus equal sagging end moments. x = L/2 is the sum of the two midspan pages. Runs locally.
- Outer Uniform Load at a Station Calculator Deflection at distance x from the wall when the uniform load starts at a and runs to the tip. x = L is the tip page. a = 0 is the full uniform curve. Runs locally.
- Overhang Arm at a Station Calculator Deflection at station z on the overhang, measured from the right support out to the load. z = a is the load page. Runs locally.
- Overhang End Deflection Calculator Deflection at a load beyond a simply supported span. δ = P a² (L + a) / (3 E I). Runs locally.
- Overhang Span at a Station Calculator Deflection at station x on the span when a load sits at the end of an overhang. x = L/2 is the span-midspan page. Runs locally.
- Overhang Span Deflection Calculator Midspan of the span moves opposite a load on the overhang. δ = −P a L² / (16 E I). Runs locally.
- Paired Load at the Load Calculator Deflection under either of two equal loads. δ = P a² (3L − 4a) / (6 E I). Runs locally.
- Paired Load Deflection Calculator Midspan deflection of two equal loads, each at distance a from the nearer support. δ = P a (3 L² − 4 a²) / (24 E I). Runs locally.
- Paired Loads at a Station Calculator Deflection at station x for two equal loads, each at distance a from the nearer support. x = L/2 is the midspan page. x = a is the under-load page. Runs locally.
- Paired Point Loads plus End Moment Calculator Deflection at station x for two equal point loads plus a sagging moment at the right end. x = L/2 adds the paired midspan page. Runs locally.
- Partial Uniform Load at a Station Calculator Deflection at distance x from the wall when a uniform load runs from the wall to a. x = a is the loaded-end page. x = L is the tip page. Runs locally.
- Person on a Ladder Calculator How far a person can climb a uniform ladder before impending slip. s is a fraction of the length from the floor. μ_wall = 0 is a smooth wall. Runs locally.
- Planar Equilibrium Calculator Sum 2-D point forces and concentrated moments, or solve two or three unknown reactions. Uses the vector and linear-algebra engines. Not a beam calculator.
- Plane Centroid Calculator Centroid of composite plane areas from each part's area and centroid. Negative area is a hole. Runs locally. Not a moment of inertia and not a beam calculator.
- Plastic Moment Calculator Fully plastic moment from a yield stress and a plastic modulus. One centroidal axis. Runs locally.
- Principal Moment Calculator Product of inertia and principal moments of a composite plane area. Ix and Iy reuse the area-moment engine. Runs locally. Not a section modulus and not a beam calculator.
- Principal Section Modulus Calculator Elastic section modulus about the principal axes. S1 = I1/c1 and S2 = I2/c2. I1, I2, and θ come from the principal-moment engine. Runs locally. Not Sx and Sy, and not bending stress.
- Rectangular Plastic Modulus Calculator Plastic moduli and shape factor of a solid rectangle. Elastic Sx and Sy come from the rectangular-section engine. Runs locally.
- Rectangular Section Calculator Centroidal Ix, Iy, and elastic section moduli of a solid rectangle from its width and height. Runs locally.
- Rectangular Shear Calculator Neutral-axis shear stress of one solid rectangle. The area moment comes from the rectangular-section engine. Runs locally.
- Rough-Wall Ladder Calculator Critical angle of a uniform ladder when both the floor and the wall are at impending slip. μ_wall = 0 recovers the smooth-wall ladder. Runs locally.
- Section Modulus Calculator Elastic section modulus of a composite plane area about its centroid. Sx = Ix/cy and Sy = Iy/cx. Ix and Iy come from the area-moment engine. Runs locally. Not bending stress and not beam deflection.
- Shear and Moment Calculator Shear and bending moment at a cut in a simply supported span. Point forces and concentrated moments only. Runs locally. Not beam deflection.
- Slip or Tip Calculator Whether a block on a level surface slips or tips under a horizontal force. Slip uses the friction engine. Tip is the moment of the weight about the leading edge. Runs locally.
- Tip Load at a Station Calculator Deflection at distance x from the wall under a tip load. δ = P x² (3L − x) / (6 E I). Runs locally.
- Tip Moment at a Station Calculator Deflection at distance x from the wall for a moment at the free end. δ = M x² / (2 E I). Runs locally.
- Tip-Peak Triangle at a Station Calculator Deflection at distance x from the wall when the triangle peaks at the tip. x = L is the tip page. Runs locally.
- Transverse Shear Calculator Shear stress at one line from the shear force, the first moment, the area moment, and the width. Runs locally.
- Triangular Load at a Station Calculator Deflection at station x for a triangular load that is zero at the left support. x = L/2 is the midspan page. Runs locally.
- Triangular Load Deflection Calculator Midspan deflection of a simply supported span with a triangular load. δ = 5 w0 L⁴ / (768 E I). Intensity is 0 at the left support. Runs locally.
- Triangular Load Maximum Calculator Largest deflection of a simply supported span with a triangular load. The peak is not at midspan. Runs locally.
- Uniform Load at a Station Calculator Deflection at station x on a simply supported uniform load. δ = w x (L³ − 2 L x² + x³) / (24 E I). Runs locally.
- Uniform Load Deflection Calculator Midspan deflection of a simply supported span with a uniform load. δ = 5 w L⁴/(384 E I). I is an input. Runs locally.
- Wall-Peak Triangle at a Station Calculator Deflection at distance x from the wall when the triangle peaks at the wall. x = L is the tip page. Runs locally.
Chemistry calculators
Amount of substance, solutions, and acid-base pH.
- Henderson–Hasselbalch Calculator Compute buffer pH = pKa + log10([A−]/[HA]). Accepts pKa or Ka. Runs locally. Not ICE equilibrium and not pH = −log10[H+].
- Molarity Calculator Compute molarity c = n/V and dilution C1·V1 = C2·V2. Runs locally. Not mole n=m/M and not Henderson–Hasselbalch.
- Mole Calculator Compute amount n = m/M and particle count N = n·N_A. N_A is CODATA 2018 exact. Runs locally. Not molarity and not Henderson–Hasselbalch.
- pH Calculator Compute pH = −log10[H+] and pOH = −log10[OH−] at 25 °C with Kw = 1e-14. Runs locally. Not Henderson–Hasselbalch and not ICE.
- Weak-Acid Equilibrium Calculator Solve monoprotic weak-acid ICE from formal C and Ka or pKa. Charge and mass balance; optional water at 25 °C. Runs locally. Not Henderson–Hasselbalch and not pH = −log10[H+] identities.
- Weak-Base Equilibrium Calculator Solve monoprotic weak-base ICE from formal C and Kb or pKb. Charge and mass balance; optional water at 25 °C. Runs locally. Not Henderson–Hasselbalch and not weak-acid ICE.
Engineering calculators
Tolerance, uncertainty, and engineering analysis tools.
- Cochran's C Calculator Compute ISO 5725-2 Cochran's C from k≥2 stated laboratory sample standard deviations. Runs locally. Not pooled s_p, not Hartley's F_max, and not a tabulated Ccrit pass/fail.
- Conformity Decision Rule Calculator Apply a binary ILAC G8-style decision to a measured value y: simple acceptance (w=0) or guarded acceptance (LSL+w ≤ y ≤ USL−w). Runs locally. Not JCGM 106 risk tables and not TUR.
- Coverage Factor Calculator Compute the two-sided Student-t coverage factor k from degrees of freedom ν and confidence p. Infinite ν uses the normal quantile. Runs locally. Not expanded U = k·u_c.
- Gauge Capability Calculator (Cg / Cgk) Compute Type-1 Cg and Cgk from repeats on a master, a reference xm, and the characteristic tolerance. frac defaults to 0.2. Runs locally. Not AIAG GRR and not process Cp/Cpk.
- Gauge R&R Calculator Compose AIAG Gauge R&R from EV, AV, and PV: GRR, TV, %GRR, and ndc. Optional range-method EV = R̄/d2. Runs locally. Not a full ANOVA study.
- Guard Band Calculator Compute a simple guard band GB=k·u and optional acceptance limits USL−GB and LSL+GB. Runs locally. Not ILAC G8 risk-based decision rules.
- Inverse-Variance Weighted Mean Calculator Combine independent results of the same measurand with the GUM H.3 inverse-variance weighted mean. Runs locally. Not combined RSS, not Type A u_A, and not GUM propagate.
- ISO 5725 Reproducibility Calculator Compute the ISO 5725 reproducibility limit from stated components s_r and s_L: s_R = √(s_r²+s_L²), R = 2.8·s_R. Runs locally. Not r from a sample, not AIAG GRR, and not combined RSS.
- Maximum Permissible Error Calculator Decide whether a measured value meets the VIM maximum permissible measurement error: pass iff |ylab−xref| ≤ MPE. Runs locally. Not an ILAC G8 spec decision, not En, and not ε-only.
- Measurement Bias Calculator Compute VIM trueness as the signed bias = x̄ − xm from repeats on a master. Runs locally. Not a single-shot measurement error, not Type A u_A, and not Cg.
- Measurement Error Calculator Compute the VIM signed measurement error ε = ylab − xref and the relative error ε/xref. Runs locally. Not percent error, not En, and not a z-score.
- Measurement Precision Calculator Compute ISO 5725 repeatability from a sample: s, CV = s/|x̄|, and r = 2.8·s. Runs locally. Not Type A u_A, not Gauge R&R EV, and not percent CV.
- Monte Carlo Tolerance Calculator 1-D Tolerance Analysis Workspace: dimensional Monte Carlo with asymmetric ±tol, correlations, sensitivity ranking, σ convergence, LSL/USL yield, simulated capability, and immutable Freeze snapshots.
- MSA Hysteresis Calculator Compute VIM / MSA hysteresis as the maximum absolute difference between increasing and decreasing indications at index-paired stations. Runs locally. Not OLS linearity, not a %Hysteresis pass/fail, and not Gauge R&R.
- MSA Linearity Calculator Fit ordinary least squares of measurement error ε = ylab − xref versus xref. Reports slope, intercept, and r². Runs locally. Not a single-master bias, not Type-1 Cg, and not a %Linearity pass/fail.
- Normalized Error Calculator Compute the proficiency-testing normalized error En from a laboratory result, a reference value, and two already-expanded uncertainties. |En| ≤ 1 is pass. Runs locally. Not zeta, not TUR, and not an ILAC G8 spec decision.
- Pooled Standard Deviation Calculator Compute a pooled standard deviation from k≥2 stated sample s_i and their degrees of freedom ν_i. Runs locally. Not Type A from one sample, not Welch–Satterthwaite ν_eff, and not ISO 21748 u of a mean.
- Process Capability Calculator (Cp / Cpk) Compute design-stage Cp, Cpk, Cpu, and Cpl from process mean, σ, LSL, and USL. Runs locally in your browser. Not Monte Carlo simulated capability.
- Process Capability Cpm Calculator Compute Taguchi Cpm from μ, σ, LSL, USL, and a target. Runs locally. Not Cp/Cpk, not Pp/Ppk, and not a 1.33 verdict.
- Process Capability Cpmk Calculator Compute Taguchi Cpmk from μ, σ, LSL, USL, and a target. Runs locally. Not Cpm, not Cpk, not Ppm, and not a 1.33 verdict.
- Process Performance Calculator (Pp / Ppk) Compute overall Pp, Ppk, Ppu, and Ppl from process observations, LSL, and USL. σ is the overall sample s. Runs locally. Not design-stage Cp/Cpk and not Type A u_A.
- Process Performance Ppm Calculator Compute overall Taguchi Ppm from observations, LSL, USL, and a target. Runs locally. Not design-stage Cpm, not Pp/Ppk, and not a 1.33 verdict.
- Process Performance Ppmk Calculator Compute overall Taguchi Ppmk from observations, LSL, USL, and a target. Runs locally. Not Cpmk, not Ppk, not Ppm, and not a 1.33 verdict.
- Proficiency-Testing z-Score Calculator Compute the ISO 13528 proficiency-testing z-score from a laboratory result, an assigned value, and the scheme SDPA σ_pt. |z| ≤ 2 is pass. Runs locally. Not zeta, not En, and not an ILAC G8 spec decision.
- Proficiency-Testing z′ Calculator Compute the ISO 13528 z′ score from a laboratory result, an assigned value, the scheme SDPA σ_pt, and the standard uncertainty of that assigned value. |z′| ≤ 2 is pass. Runs locally. Not z-score, not zeta, and not En.
- Repeatability from Duplicates Calculator Compute ISO 5725 repeatability s_r from m≥2 duplicate differences. Runs locally. Not Type A from a sample of observations, not r = 2.8·s, and not AIAG GRR EV = R̄/d2.
- Test Uncertainty Ratio Calculator Compute the two-sided test uncertainty ratio TUR from an already-expanded U and a specification interval. Runs locally. Not a pass/fail, not a guard band, and not combined RSS.
- Tolerance Stack-up Calculator Combine dimensional tolerances with worst-case sum or RSS root-sum-square. Basic magnitude list or Engineering mode with nominal, ±tol, and direction.
- Type A Uncertainty Calculator Compute Type A standard uncertainty from repeated observations: mean, sample s, and u_A = s/√n. Runs locally. Not GUM combination and not Monte Carlo.
- Type B Degrees of Freedom Calculator Compute GUM G.4.2 Type B degrees of freedom from a stated standard uncertainty u and its standard uncertainty σ(u). σ(u)=0 → ν is infinite. Runs locally. Not Type B u_B, not Welch ν_eff, and not U = k·u_c.
- Type B Uncertainty Calculator Compute Type B standard uncertainty from a half-width a. Rectangular u_B = a/√3, triangular u_B = a/√6. Runs locally. Not GUM combination and not Monte Carlo.
- Uncertainty of a Mean from Precision Calculator Compute the ISO 21748 standard uncertainty of a mean of n≥2 replicates from stated precision components s_r and s_L. Runs locally. Not R = 2.8·s_R, not Type A from a sample, and not U = k·u.
- Uncertainty Propagation Calculator Propagate measurement uncertainty using GUM linear propagation, covariance, uncertainty budgets, or Monte Carlo simulation. Optional correlation ρ and coverage factor k → U. Runs locally in your browser.
- Welch–Satterthwaite Calculator Compute GUM G.4 effective degrees of freedom ν_eff from standard uncertainty components u_i and their ν_i. Runs locally. Not combined RSS and not expanded U = k·u_c.
- Worst-Case Tolerance Analysis Calculator 1-D linear dimensional tolerance stack: worst-case Σ|tol| with RSS comparison. Deterministic bound under declared limits — pairs with Tolerance Stack-up and Monte Carlo.
- Zeta-Score Calculator Compute the proficiency-testing zeta-score from a laboratory result, a reference value, and two standard uncertainties. |ζ| ≤ 2 is pass. Runs locally. Not En, not TUR, and not an ILAC G8 spec decision.
Time calculators
Age, dates, duration, and world clocks.
- Age Calculator Calculate exact age in years, months, and days from a birth date to today or a chosen date. Runs locally in your browser. Free online tool — no sign-up.
- Alaska / Anchorage Time Live local time in Anchorage and most of Alaska (America/Anchorage). See AKST UTC−9, AKDT UTC−8, DST dates, and how Alaska Time compares to other U.S.
- Bangkok / Thailand Time Show current time in Bangkok (Indochina Time, UTC+7) with a simple world-clock style readout. Runs locally in your browser. Free online tool — no sign-up.
- Beijing / China Time Live local time in Beijing and all of mainland China (Asia/Shanghai). China Standard Time (CST) is UTC+8 year-round with no Daylight Saving Time.
- Chicago / Central Time Live local time in Chicago (America/Chicago). See CST UTC−6, CDT UTC−5, U.S. DST dates, and how Central Time compares to Eastern, Mountain, and Pacific.
- Days in a Year How many days in 1 year? Free online tool — no sign-up. Clear formulas and worked examples. Built for quick, accurate checks. Runs locally in your browser.
- Denver Time Live local time in Denver (America/Denver). See MST UTC−7, MDT UTC−6, U.S. DST dates, and how Mountain Time compares to Pacific, Central, and Eastern.
- Hawaii Time Live local time in Honolulu and Hawaii (Pacific/Honolulu). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- Hong Kong Time Live local time in Hong Kong (Asia/Hong_Kong). Hong Kong Time is UTC+8 year-round with no Daylight Saving Time. Runs locally in your browser. Try it free.
- Hours in a Week Use the free Hours in a Week on CalculatorX for fast local results. Clear formulas, assumptions, and worked examples on the page. No account needed.
- Hours in a Year Use the free Hours in a Year on CalculatorX for fast local results. Clear formulas, assumptions, and worked examples on the page. No account needed.
- India Time (IST) Live local time in India (Asia/Kolkata). Indian Standard Time is UTC+5:30 year-round with no Daylight Saving Time — one zone for the whole country.
- Los Angeles Time Live local time in Los Angeles (America/Los_Angeles). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- Minutes in a Day Use the free Minutes in a Day on CalculatorX for fast local results. Clear formulas, assumptions, and worked examples on the page. Fast and free.
- Months in a Year Use the free Months in a Year on CalculatorX for fast local results. Clear formulas, assumptions, and worked examples on the page. Fast and free.
- Nepal Time Live local time in Kathmandu and Nepal (Asia/Kathmandu). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- New York Time Live local time in New York (America/New_York). See EST UTC−5, EDT UTC−4, U.S. DST dates, and how Eastern Time compares to Central, Mountain, and Pacific.
- Pakistan Time Live local time in Karachi and Pakistan (Asia/Karachi). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- Philippines Time Live local time in Manila and the Philippines (Asia/Manila). Free online tool — no sign-up. Built for quick, accurate checks. Runs locally in your browser.
- Phoenix Time Live local time in Phoenix, Arizona (America/Phoenix). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- Seconds in a Day Use the free Seconds in a Day on CalculatorX for fast local results. Clear formulas, assumptions, and worked examples on the page. Fast and free.
- Seconds in a Year How many seconds in 1 year (365 d)? Works offline-ready. Free online tool — no sign-up. Runs locally in your browser. Clear formulas and worked examples.
- Seconds in an Hour How many seconds in 1 hour? Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser. Simple and accurate.
- Seoul Time Live local time in Seoul and South Korea (Asia/Seoul). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- Singapore Time Live local time in Singapore (Asia/Singapore). Singapore Time is UTC+8 year-round with no Daylight Saving Time. Runs locally in your browser. Try it free.
- Taiwan Time Live local time in Taipei and Taiwan (Asia/Taipei). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- Tokyo / Japan Time Live local time in Tokyo and Japan (Asia/Tokyo). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- UK / London Time Live local time in London and the UK (Europe/London). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- UTC Time Live UTC clock (UTC+0). Free online tool — no sign-up. Clear formulas and worked examples. Mobile-friendly and privacy-first. Runs locally in your browser.
- Weeks in a Month Count how many weeks fall in a given calendar month, with options for week-start conventions. Runs locally in your browser. Free online tool — no sign-up.
- Weeks in a Year Use the free Weeks in a Year on CalculatorX for fast local results. Clear formulas, assumptions, and worked examples on the page. No account needed.
Financial calculators
Interest, VAT, GST, and related finance tools.
- Break-Even Calculator Find break-even units or sales from fixed costs, variable cost per unit, and selling price. Runs locally in your browser. Free online tool — no sign-up.
- CAGR Calculator Calculate compound annual growth rate (CAGR) from beginning value, ending value, and years. Runs locally in your browser. Free online tool — no sign-up.
- Compound Interest Calculator Project future value with compound interest from principal, rate, compounding frequency, and time. Optional contributions. Runs locally in your browser.
- Discount Calculator Apply a percent discount to a price and show savings and final amount. Runs locally in your browser. Free online tool — no sign-up. Try it free.
- GST Calculator Add or remove GST from prices at a chosen GST rate for inclusive/exclusive totals. Runs locally in your browser. Free online tool — no sign-up.
- Loan Amortization Calculator Build a loan amortization schedule: payment, interest, principal, and remaining balance by period. Runs locally in your browser. Try it free.
- Loan Payment Calculator Calculate fixed monthly loan payments from principal, annual rate, and term. Shows amortization-style payment math. Runs locally in your browser.
- Markup Calculator Calculate selling price or markup percentage from cost and desired margin. Runs locally in your browser. Free online tool — no sign-up. Try it free.
- Present Value Calculator Discount a future amount to present value at a chosen rate and number of periods. Runs locally in your browser. Free online tool — no sign-up.
- Profit Margin Calculator Compute gross or net profit margin from revenue and cost (or profit). Shows margin vs markup differences. Runs locally in your browser. Try it free.
- ROI Calculator Measure return on investment as gain or loss versus cost, with percentage ROI and net profit. Runs locally in your browser. Free online tool — no sign-up.
- Savings Goal Calculator Estimate deposits needed to reach a savings goal given rate, compounding, and timeline. Runs locally in your browser. Free online tool — no sign-up.
- Simple Interest Calculator Calculate simple interest and total amount from principal, rate, and time—no compounding. Runs locally in your browser. Free online tool — no sign-up.
- VAT Calculator Add or remove VAT from a net or gross price at a chosen VAT rate. Runs locally in your browser. Free online tool — no sign-up. Fast and free.
Lighting calculators
Lumens, lux, candela, and lighting conversions.
- Candela to Lumen Calculator Convert candela (cd) to lumens (lm) using beam angle: lm = cd × 2π(1 − cos(θ/2)). Reverse lumens to candela. Includes solid angle and full-sphere 4π.
- Candela to Lux Calculator Convert luminous intensity in candela to illuminance in lux at a given distance (inverse-square). Runs locally in your browser. Try it free.
- Foot-Candles to Lux Calculator Convert foot-candles (fc) to lux (lx): lx = fc × 10.76391. Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- Lumen to Candela Calculator Convert lumens (lm) to candela (cd) using beam angle: cd = lm ÷ 2π(1 − cos(θ/2)). Reverse candela to lumens. Includes solid angle and full-sphere 4π.
- Lumen to Lux Calculator Convert lumens (lm) to lux (lx): lx = lm ÷ A. Use area in m² or ft², or isotropic sphere radius. Reverse lux to lumens. Runs locally in your browser.
- Lumen to Millicandela Calculator Convert lumens (lm) to millicandela (mcd): mcd = 1000 × lm ÷ 2π(1 − cos(θ/2)). Reverse mcd to lumens. Runs locally in your browser. Fast and free.
- Lumen to Watt Calculator Convert lumens (lm) to watts (W) using luminous efficacy: W = lm ÷ η (lm/W). Reverse watts to lumens. Includes typical LED, CFL, halogen, and incandescent.
- Lux to Candela Calculator Convert lux (lx) to candela (cd) at a distance: cd = lx × d² (meters) or cd = lx × d(ft)² ÷ 10.76391. Reverse candela to lux. Runs locally in your browser.
- Lux to Lumen Calculator Convert lux (lx) to lumens (lm): lm = lx × A. Use area in m² or ft², or isotropic sphere radius. Reverse lumens to lux. Runs locally in your browser.
- Lux to Watt Calculator Convert lux (lx) to watts (W): W = (lx × A) ÷ η. Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- Watt to Lumen Calculator Convert watts (W) to lumens (lm): lm = W × η (lm/W). Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.
- Watt to Lux Calculator Convert watts (W) to lux (lx): lx = (W × η) ÷ A. Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.