One of the main activities of the DRUM TG is to inventory the many different systems that have been created to implement units of measurement in digital systems. These range from encoding standards, to latex presentation, to ontologies, and many more. Below you will find links to available unit representation systems. If you know of a system that is missing, please contact Stuart Chalk.
This data was last reviewed on: January 11, 2026
Encoding formats¶
| System | Maintainer | Domain |
|---|---|---|
| VO Units | IVOA | Astronomy |
| Unified Code for Units of Measurement (UCUM) | Regenstrief Institute | Medicine |
Vocabularies¶
| System | Maintainer | Domain |
|---|---|---|
| NERC P06 - BODC-approved data storage units | BODC | Environmental Science |
| UNECE Rec 20 - Units of Measure in Trade | UNECE | International Trade |
| UnitsML | Metanorma | General |
| WMO Codes Registry - Measurement Unit | WMO | Weather |
Presentation Formats¶
| System | Maintainer | Language | Domain |
|---|---|---|---|
| siunitx | Joseph Wright | LaTex | General |
| mhchem (\pu function) | Martin Hensel | LaTex | Chemistry |
Ontologies¶
| System | Maintainer | Domain |
|---|---|---|
| Ontology of Units of Measure (OM) | Hajo Rijgersberg | General |
| Quantities, Units, Dimensions and Datatypes (QUDT) | QUDT.org | General |
| SI Reference Point (SIRP) | BIPM | General |
| SWEET Ontology - Units | ESIP | Environmental Science |
| Unit Ontology | Robert Hoehndorf | Biological Science |
Packages / Libraries¶
| System | Maintainer | Language | Domain |
|---|---|---|---|
| Astropy | NumFOCUS | Python | Astronomy |
| Fhir.Metrics | Firely | C++ | Healthcare |
| craft-units | NYStudio107 | Python/Craft | General |
| cf-units | SciTools | Python | Climate |
| go-units | bcicen | Go | General |
| mathjs | Jos de Jong | JavaScript/Node.js | General |
| Measurement Units for R | PhpUnitsOfMeasure | PHP | General |
| PHP Units of Measure | R Quantities | R | General |
| Pint | Hernan Grecco | Python | General |
| ruby-units | Kevin Olbrich | Ruby | General |
| safe-units | Jonah Scheinerman | TypeScript | General |
| UDUNITS | UCAR | C | Earth Science |
| units | LLNL | C++ | General |
| Units | Nic Holthaus | C++ | General |
| Unit API | Werner Keil | Java | General |
| Units and Quantities | Wolfram | Wolfram Language | General |
| UnitsNet | Andreas Gullberg Larsen | .NET | General |
| UnitWise | Josh W Lewis | Ruby | General |
| Unity [of VOUnits] | Norman Gray | Java/C | Astronomy |
| uom | Mark Boutin | Rust | General |
OS Packages¶
| System | Maintainer | OS | Domain |
|---|---|---|---|
| GNU Units | Free Software Foundation | GNU | Any |
Legacy Systems¶
csunits (C# framework)
Hackathon-Ayurveda (conversion of ancient Ayurveda units)
Library for Quantity Kinds and Units (w3c work)
MeasurementJs (JavaScript implementation)
PixelMed Java UCUM Toolkit (implementation of UCUM in Java)
pyucum (UCUM conversion and verification in Python)
Squants (package for the Scala programming language)
UnitOf (for Java, JavaScript, C#)
Unit Converter (for PHP)
UOMo (units for Eclipse - incubating)