Unambiguous models for scientific units of measure

UnitsML provides a set of models for unambiguously encoding and identifying scientific units of measure and quantities — usable in XML and other markup languages, improving interoperability across information systems and scientific disciplines.

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mkgsAKmolcdNJWPaHzVΩ

Trusted by leading standards

The authoritative unit standard in XML

UnitsML powers mission-critical measurement encoding across shipbuilding, industrial automation, and scientific data exchange.

OCX Consortium

The vessel-specific XML standard for model-based class approval, used by DNV, NAPA, and major shipbuilders. OCX encodes every physical quantity with UnitsML to keep hull measurements precise across CAD tools.

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IEC CDD

The IEC Common Data Dictionary is the central repository of standardized units for industrial automation. Through IEC/TS 62720 and ECLASS, its unit identifiers align 1:1 with UnitsML.

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Browse UnitsDB

Explore the complete database of 380+ units, 199 quantities, 92 dimensions, and more — all with interactive search, cross-linking, and JSON-LD downloads.

0 Units0 Quantities0 Dimensions0 Prefixes0 Systems

Open UnitsDB

mmetreL

kgkilogramM

NnewtonL·M·T⁻²

PapascalL⁻¹·M·T⁻²

JjouleL²·M·T⁻²

WwattL²·M·T⁻³

The UnitsML Ecosystem

An integrated suite of schemas, databases, and tools for encoding scientific units of measure.

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How UnitsML Works

Three steps to unambiguous unit encoding in scientific data.

XML

<UnitsML xmlns="https://schema.unitsml.org/unitsml/1.0">
  <UnitSet>
    <Unit xml:id="m" dimensionURL="#L">
      <UnitName>metre</UnitName>
      <UnitSymbol>SI</UnitSymbol>
    </Unit>
  </UnitSet>
</UnitsML>