units-of-measurement 1.0.0

Comprehensive units of measurement dataset — 2,959 units, 121 physical quantities, conversion factors, 11 measurement systems

Units of Measurement

A comprehensive collection of units of measurement in JSONL format, covering 121 physical quantities and 11 measurement systems.

Files

The json/ directory contains three JSONL files (one JSON object per line):

units_of_measurement.jsonl (2,959 entries)

The comprehensive, merged dataset. This is the file most users will want. It combines the SI and UOM datasets below into a single superset with a unified schema covering all fields.

Fields:

Field	Type	Description
unit	string	Unit name (e.g., "kilometer", "pound")
prefix	string or null	SI prefix if applicable (e.g., "kilo", "milli")
symbol	string	Unit symbol (e.g., "km", "lb")
plural	string	Plural form (e.g., "kilometers", "pounds")
property	string	Physical quantity measured (e.g., "length", "mass")
conversion_factor	number	Multiplier to convert to the reference unit
conversion_offset	number	Additive offset for temperature conversions (present only for Celsius and Fahrenheit)
reference_unit	string	The SI coherent unit that conversion_factor is relative to
alternate_unit	array of strings	Alternate names for the unit (present only where applicable, e.g., "metre" for "meter")
system	string	Measurement system (see below)

si_units.jsonl (812 entries)

SI base units, SI derived units with special names, and non-SI units accepted for use with the SI (per the SI Brochure, 9th Edition). Each unit includes full SI prefix expansions (all 24 prefixes from quecto through quetta). Uses US English spellings ("meter", "liter").

Fields: unit, prefix, symbol, property, alternate_unit (optional), system

uom.jsonl (2,660 entries)

Units parsed from the Rust uom crate by Mike Boutin. Covers 117 physical quantities across multiple measurement systems, with conversion factors relative to the SI coherent unit for each quantity.

Fields: unit, symbol, plural, property, conversion_factor, conversion_offset (optional), reference_unit, system

Measurement Systems

System	Description
SI	International System of Units
Metric	Metric units not part of SI (e.g., bar, calorie, liter, tonne)
Imperial	British Imperial units (e.g., foot, pound, gallon)
CGS	Centimetre-Gram-Second system (e.g., dyne, erg)
Nautical	Nautical units (nautical mile, knot)
Astronomical	Astronomical units (astronomical unit, light year, parsec)
Atomic/Natural	Atomic and natural units (Bohr radius, hartree)
IEC	IEC binary prefixes for information (kibibyte, mebibyte, etc.)
Information	Information units (bit, byte, shannon, nat)
Ancient Roman	Historical Roman units of length, mass, area, and volume
other	Units not clearly belonging to a single system

Conversion Factors

Each entry's conversion_factor is the multiplier to convert one unit to the reference_unit for that property. For example:

• kilometer: conversion_factor: 1000.0, reference_unit: "meter" -- 1 km = 1000 m
• liter: conversion_factor: 0.001, reference_unit: "cubic meter" -- 1 L = 0.001 m^3
• pound: conversion_factor: 0.4535924, reference_unit: "kilogram" -- 1 lb = 0.4536 kg

For temperature units with a conversion_offset, the conversion to the reference unit (kelvin) is: value_in_kelvin = value * conversion_factor + conversion_offset.

Data Sources

• SI Brochure (9th Edition, 2019) -- Bureau International des Poids et Mesures (BIPM). Source for SI base units, derived units, and non-SI units accepted for use with the SI.
• uom -- Units of Measurement Rust crate by Mike Boutin, licensed under MIT / Apache-2.0. Source for conversion factors, plurals, and extended unit coverage across multiple measurement systems. See THIRD-PARTY-LICENSES for the full license text.

License

This project is licensed under the MIT License.