HomeCalculatorsPhysicsUnitsCelsius to Kelvin Converter
Physics calculator

Celsius to Kelvin Converter

Convert between Celsius and Kelvin with hard absolute-zero checks. Runs locally in your browser.

Instant result
Result
—

Enter values to calculate.

Inputs—
Mode—
Formula—
Trust summary CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance
Input interpretation
Enter values to calculate.
Result
—
Assurance
Engineering
Declared partition coverage
PASS · 2/2 declared partitions (celsius-kelvin, invalid-domain) · Matrix
Known limitations
  • Absolute zero floor
  • Core CVP does not include live graph, viewport, or pointer interaction.
Model
Celsius ↔ Kelvin conversion.
Scope
ITS-90 offset 273.15
Verification
Engine tested · Source checked · v1.0.2 · CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· View Manifest · CVP overview · Specification
Versions
Calculation 1.0.2 · CVP protocol 1.0.0-proposed · Evidence 2026-11-09.uuce-canonical-units-v1
Verification revision
2026-11-09.uuce-canonical-units-v1 · 2/2 property · digest 45226e9604a7
Legacy regression
6/6 tests · Production surface contract 6/6
Trust layers
Verification VERIFIED · Production CURRENT · Overall CVP state: VERIFIED under CVP 1.0.0-proposed
Reference
O1 model · O2 expected_values · O2 numerical_behavior
Interfaces
PASS · UI (SSR) / REST / MCP — ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 3/3 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
Supplemental domain review
Internal · Pass · CalculatorX electrical review
Named expert review
Not performed
CVP suite
6/6 golden · 5/5 CVP boundary · 8/8 invalid · 2/2 property · 2/2 metamorphic · 1/1 round-trip · 7/7 cross-interface · 6/6 CVP contract · Manifest
Sources
  • SI temperature units — Kelvin / Celsius relation
  • NIST / SI temperature — kelvin and Celsius
Sources
Evidence
2 legacy golden · 2 legacy boundary · legacy regression suite · 6/6 oracle-backed golden · 8/8 invalid · Artifact integrity PASS · CalculatorX electrical review
This calculator CURRENT · Public schema 1.0.2 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓
Semantic contract
PASS
Full verification

Manifest identity, reference classes, interfaces, suite, and production records.

Formulas

Core equations used by this calculator.

°C → KK = °C + 273.15
K → °C°C = K − 273.15
iNot a single multiply — absolute zero is 0 K = −273.15 °C.

How to use

1

Choose °C → K or K → °C

Same offset conversion in either direction.

2

Enter the temperature

Kelvin must be ≥ 0 when converting from K.

3

Read the converted value

K = °C + 273.15 (exact offset used by this tool).

Example calculations

Common configurations with formula and result.

ϟ

25 °C

room temperature

25+273.15
298.15 K

Celsius to Kelvin converter specification

Version 1.0.2 · Engine tested · Supplemental domain review · Internal · 2026-08-09

Calculation status

Review policy · Evidence · Reviewed by CalculatorX electrical review

Definition
Affine conversion: K = °C + 273.15 and °C = K − 273.15. Kelvin is absolute and must be ≥ 0.
What it calculates
Celsius ↔ Kelvin conversion.
Inputs
  • mode c-k|k-c
  • value
Outputs
  • K or °C number
Formula
K=C+273.15
Assumptions
  • ITS-90 offset 273.15
Units
  • °C, K
Boundary conditions
  • Finite JSON numbers and bounded decimal strings are accepted. Nondecimal strings are rejected.
  • Nonzero results outside the binary64 range are rejected.
  • K<0 → VALUE_OUT_OF_RANGE
  • missing value → MISSING_REQUIRED_INPUT
Example
25 °C → 298.15 K
Validation cases

1 published on this page · 6/6 tests · Production surface contract 6/6 · View evidence

  • c-k value=25 → 298.15
Sources
  • SI temperature units — Kelvin / Celsius relation
    Supports: K = °C + 273.15
  • NIST / SI temperature — kelvin and Celsius
    Supports: T/K = t/°C + 273.15
Last reviewed
2026-08-09
Reviewed by
CalculatorX electrical review
Calculation version
1.0.2

Background

Interpretation and common distinctions.

Convert Celsius ↔ Kelvin with Trusted Template guards.

Supported and not supported

Supported — Bidirectional °C↔K · API units.temperature.celsius_kelvin

Not supported — Fahrenheit / Rankine (use temperature converters)

Agent / API notes

Capability id: units.temperature.celsius_kelvin · tool id: celsius-kelvin · pin 1.0.2.

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Frequently asked questions

Key distinctions behind the calculation.

Can Kelvin be negative?

No. The API returns VALUE_OUT_OF_RANGE for K < 0 or °C < −273.15.