all-units

Universal unit converter — 13 categories, 100+ units. Zero dependencies. TypeScript-first.

Features

• 13 categories: length, mass, temperature, area, volume, time, speed, pressure, energy, power, digital storage, angle, frequency
• 100+ units with precise conversion factors
• Fluent API: convert(100).from('cm').to('m') — readable and chainable
• Direct API: convert(100, 'cm', 'm') — compact one-liner
• Full TypeScript types with IDE autocomplete for all unit names
• Throws a clear error when units are incompatible (different categories)
• Zero runtime dependencies
• Works in Node.js, Deno, Bun, and modern browsers
• ESM + CommonJS dual build

Install

npm install all-units
# or
pnpm add all-units
# or
yarn add all-units

Usage

import { convert } from 'all-units'

// Fluent API (recommended)
convert(100).from('cm').to('m')          // 1
convert(1).from('km').to('mi')           // 0.621371
convert(0).from('C').to('F')             // 32
convert(100).from('C').to('F')           // 212
convert(1).from('kg').to('lb')           // 2.204623
convert(1).from('kWh').to('J')           // 3600000
convert(1).from('GB').to('MB')           // 1000   (SI)
convert(1).from('GiB').to('MiB')         // 1024   (IEC)
convert(180).from('deg').to('rad')       // 3.14159 (π)
convert(1).from('atm').to('bar')         // 1.01325

// Direct API
convert(1000, 'm', 'km')                 // 1
convert(32, 'F', 'C')                    // 0

CommonJS (require) is also supported:

const { convert } = require('all-units')

convert(1, 'mi', 'km')  // 1.609344

API

convert(value, from, to)

Direct style — pass value, source unit and target unit in one call.

convert(value: number, from: Unit, to: Unit): number

convert(value).from(unit).to(unit)

Fluent style — build the conversion step by step.

convert(value: number): FromStep
// .from(unit).to(unit) → number

Both styles throw Error if:

• A unit string is unknown
• The two units belong to different categories (e.g. 'cm' → 'kg')

canConvert(from, to)

Returns true if the two units are in the same category.

canConvert('cm', 'm')    // true
canConvert('cm', 'kg')   // false
canConvert('xyz', 'm')   // false

getCategory(unit)

Returns the category name of a unit, or undefined if unknown.

getCategory('km')    // 'length'
getCategory('C')     // 'temperature'
getCategory('GiB')   // 'digital'

possibilities(unit)

Returns all units that are compatible with the given unit (same category). Useful for populating UI dropdowns.

possibilities('km')  // ['um', 'mm', 'cm', 'm', 'km', 'in', 'ft', 'yd', 'mi', 'nmi']
possibilities('C')   // ['C', 'F', 'K', 'R']
possibilities('GB')  // ['bit', 'B', 'KB', 'MB', 'GB', 'TB', 'PB', 'KiB', 'MiB', 'GiB', 'TiB', 'PiB']

listUnits()

Returns all units grouped by category, or just the list for one category.

listUnits()            // { length: ['mm', 'cm', 'm', ...], temperature: [...], ... }
listUnits('length')    // ['um', 'mm', 'cm', 'm', 'km', 'in', 'ft', 'yd', 'mi', 'nmi']

Supported units

Length

| Unit | Name | |---|---| | um | Micrometre | | mm | Millimetre | | cm | Centimetre | | m | Metre | | km | Kilometre | | in | Inch | | ft | Foot | | yd | Yard | | mi | Mile | | nmi | Nautical mile |

Mass

| Unit | Name | |---|---| | mg | Milligram | | g | Gram | | kg | Kilogram | | t | Metric ton | | oz | Ounce | | lb | Pound | | st | Stone |

Temperature

| Unit | Name | |---|---| | C | Celsius | | F | Fahrenheit | | K | Kelvin | | R | Rankine |

Area

mm2 cm2 m2 km2 in2 ft2 yd2 mi2 ha (hectare) ac (acre)

Volume

ml cl dl l m3 tsp tbsp fl_oz cup pt qt gal (US) uk_gal (UK)

Time

ms s min h d wk mo yr

Speed

m/s km/h mph knot ft/s

Pressure

Pa kPa MPa bar atm psi mmHg inHg

Energy

J kJ cal kcal Wh kWh BTU eV

Power

W kW MW GW hp

Digital storage

| Unit | Standard | Size | |---|---|---| | bit | — | 1 bit | | B | — | 1 byte | | KB MB GB TB PB | SI (powers of 10) | 10³ … 10¹⁵ bytes | | KiB MiB GiB TiB PiB | IEC (powers of 2) | 2¹⁰ … 2⁵⁰ bytes |

Angle

deg (degree) rad (radian) grad (gradian)

Frequency

Hz kHz MHz GHz

Development

git clone https://github.com/MaxGrushevsky/unit-convert.git
cd unit-convert
npm install

npm run build         # compile to dist/
npm test              # run tests once
npm run test:watch    # run tests in watch mode
npm run typecheck     # TypeScript type-check only

License

MIT