This data repository is used in conjunction with UnitsML.

Sources include:

  • BIPM SI Brochure

  • NIST SP 811

  • ISO 80000 series

  • (in some cases, "Encyclopaedia of Scientific Units, Weights and Measures, Their SI Equivalences and Origins" by François Cardarelli, is consulted)

Conversion factors here are not updated with the revised SI.