Guide to how to use the SI units for scientists in the United States.

Electropedia is produced by the IEC, the world’s leading organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as “electrotechnology”. Electropedia (also known as …

Description of quantity, unit and symbol presentation for use in chemistry

As part of the CDD there exist a section that describes units of measure with distinct codes

Character string encoding for numerical values and units which: i) is unambiguous in all locales; ii) uses only "Portable Character Set" [PCS] characters matching "Basic Latin" characters in Plane 0 of the …

Terms approved for use by British Oceanographic Data Centre (BODC) to describe the measurement units for data held in its repositories.

The Ontology of units of Measure and related concepts (OM) models concepts and relations important to scientific research. It has a strong focus on units and quantities, measurements, and dimensions.

The Ontology of units of Measure (OM) 2.0 models concepts and relations that underlie the formulation of quantitative knowledge in scientific research. It has a strong focus on units, quantities, measures, and …

Grew out of work with NASA. This version is now deprecated.

QUDT.org is a 501(c)(3) public charity nonprofit organization founded to provide semantic specifications for units of measure, quantity kind, dimensions and data types. QUDT is an advocate for the development and implementation …

SWEET is a highly modular ontology suite with ~6000 concepts in ~200 separate ontologies covering Earth system science. SWEET is a mid-level ontology and consists of nine top-level concepts that can be …

This service provides information about SI units, prefixes, constants, quantities, decisions in addition to some other tools and parsing services.

The Unified Code for Units of Measure is a code system intended to include all units of measures being contemporarily used in international science, engineering, and business. The purpose is to facilitate …

Codes for Units of Measurement used in the International Trade:

An ontology of units of measurements. The ontology is provided under a CC-BY license.

Wikidata is a free, collaborative, multilingual, secondary database, collecting structured data to provide support for Wikipedia, Wikimedia Commons, the other wikis of the Wikimedia movement, and to anyone in the world.