Metre
mcx:m · Length
The metre is defined by fixing the speed of light in vacuum at 299,792,458 m/s. The second is defined through the caesium-133 transition frequency.
- Quantity kind
- Length
- SI dimension
L- Allowed roles
- Scalar
- Unit system / convention
- Coherent SI
- Registry code
m
Scope and distinctions
The metre is the reference unit for length. International and U.S. survey feet use separate unit IDs.
Available operations
UUCE executable Preview · Use cx:m with a compatible unit and a pinned snapshot.
These links open existing tools under their own contracts. They have not been migrated to the new unit registry.
- Metres to feet Existing converter
Verification scope
- UUCE conversion capability
units.convert@0.1.1· VERIFIED- Production binding at publication
- CURRENT
The definition lifecycle describes this registry entry. CVP status describes the conversion capability and the cases and rejection partitions in its Manifest. CVP Manifest · Public replay cases
Candidate is a registry lifecycle state. It is not a completed review or CVP verification.
Definition sources
- BIPM — The International System of Units (SI)
9th edition, version 4.01, June 2026
Section 2.3.1, SI base units
Source checked:Definition metadata attributed to BIPM; brochure licensed CC BY 4.0.
Definition and registry versions
- Definition revision
- 1.1.0
- Registry snapshot
- 0.3.0-preview.3 · preview
- Definition lifecycle
- candidate
- Definition owner
- core.metrology
- Definition digest
9a3761fd70b38a01d6d5f288f93d22061a36e0b7b2463cd5c6dee6fcd2c1e678- Definition dependency digest
2429755b49196082d4ccbf3188063c69cafb145d54eaa6d0406735a82e231e95
Digests identify definition content; they are not CVP evidence or production attestations.