#measurement

The UN/ECE Recommendation 20 unit-of-measure codes — the codes used to identify units of measure in trade documents, invoices and EDI messages — as an API. The reference a customs, ERP or e-invoicing system needs. Each unit (for example KGM = kilogram, MTR = metre, LTR = litre, C62 = one/each, TNE = tonne, MTK = square metre) carries a 2–3 character common code, a name, the unit symbol, a description and a status (active or deprecated). Look a code up, reverse-look-up the code(s) for a symbol (kg → KGM), search by name or symbol, or list every code filtered by status. This is the unit-of-measure CODE register — distinct from unit-api, which performs unit-conversion maths. Served from memory — always fast.

api.oanor.com/unitcodes-api

Fast, deterministic unit conversion across 10 categories — length, mass, temperature, area, volume, speed, time, digital storage, pressure and energy. Convert any value between compatible units and list the full unit catalog per category. Fully local compute (no third-party upstream), so responses are instant and always available. Ideal for calculators, e-commerce, logistics, engineering tools, dashboards and chatbots.

api.oanor.com/unit-api