Units-of-measurement (UOM) provides URLs for Unified Code for Units of Measure (UCUM) codes, and mappings to a number of units ontologies and systems, in human- and machine-readable linked data formats.

UOM currently supports International System of Units (SI) "metric" units and prefixes (as used in UCUM), and a number of non-SI units. It does not currently support UCUM's "non-units" using {} syntax.

UOM currently supports mapping to (in alphabetical order):

This service runs on the units-of-measurement Python package.