Unit Converter

A simple, extensible TypeScript unit conversion library. Convert between units with a clean, intuitive API.

Example UI:

Live demo:

Live demo

Installation

npm install unit-converter-js

Quick Start

import convert from 'unit-converter-js'

// Length
convert(5, 'miles').to('kilometers')     // → 8.0467
convert(10, 'feet').to('centimeters')   // → 304.8

// Mass
convert(5, 'kilograms').to('grams')     // → 5000
convert(10, 'pounds').to('kilograms')   // → 4.53592

// Temperature
convert(0, 'celsius').to('fahrenheit')  // → 32
convert(32, 'fahrenheit').to('celsius') // → 0

// Volume
convert(1, 'gallons').to('liters')      // → 3.78541

// Speed
convert(100, 'kilometersperhour').to('meterspersecond') // → 27.78

API

All conversions follow the same simple pattern:

convert(value, unitName).to(targetUnitName)

Examples:

convert(10, 'miles').to('kilometers')           // 16.0934
convert(5, 'kilograms').to('pounds')            // 11.0231
convert(100, 'kilometersperhour').to('meterspersecond')       // 27.78
convert(1, 'gallons').to('liters')              // 3.78541

Supported Units

Length

meters • kilometers • centimeters • millimeters • miles • feet • inches

Symbols: m • km • cm • mm • mi • ft • in

Mass

kilograms • grams • milligrams • pounds • ounces

Symbols: kg • g • mg • lb, lbs • oz

Temperature

celsius • kelvin • fahrenheit

Symbols: °C, C • K • °F, F

Volume

liters • milliliters • gallons • cups • pints • fluidounces

Symbols: l, L • ml, mL • gal • cup • pt • fl oz, floz

Area

squaremeters • squarekilometers • hectares • acres • squarefeet • squaremiles

Symbols: m², m2 • km², km2 • ha • ac • ft², ft2 • mi², mi2

Time

seconds • milliseconds • minutes • hours • days • weeks • years

Symbols: s, sec • ms • min • h, hr • d • wk • yr, y

Speed

meterspersecond • kilometersperhour • milesperhour • knots • feetpersecond

Symbols: m/s, mps • km/h, kmh • mph • kt • ft/s, fps

Pressure

pascals • bars • psi • atmospheres • millimetersmercury • kilopascals

Symbols: Pa • bar • psi • atm • mmHg • kPa

Data Storage

bytes • kilobytes • megabytes • gigabytes • terabytes • petabytes

Symbols: B • KB • MB • GB • TB • PB

Energy

joules • kilojoules • calories • kilocalories • btu • watthours

Symbols: J • kJ • cal • kcal • BTU, Btu • Wh

Power

watts • kilowatts • megawatts • horsepower • btuperhour

Symbols: W • kW • MW • hp • BTU/h

Force

newtons • kilonewtons • dynes • poundsforce • kilogramforce

Symbols: N • kN • dyn • lbf • kgf

Angle

degrees • radians • gradians • arcminutes • arcseconds

Symbols: °, deg • rad • grad • ' • "

Frequency

hertz • kilohertz • megahertz • gigahertz • rpm

Symbols: Hz • kHz • MHz • GHz • rpm

Density

kilogramspermetercubed • gramspercentimetercubed • poundsperfoot • poundspergallon

Symbols: kg/m³, kg/m3 • g/cm³, g/cm3 • lb/ft³, lb/ft3 • lb/gal

Illuminance

lux • footcandles • lumenspermetersquared

Symbols: lx • fc • lm/m², lm/m2

Viscosity

centistokes • stokes • centipoise • poise • pascalseconds

Symbols: cSt • St • cP • P • Pa·s, Pas

Concentration

molarity • ppm • ppb • percent • ppt

Symbols: M • ppm • ppb • % • ppt

Contributing

Want to add more units or categories? Contributions are welcome!

See CONTRIBUTING.md for:

• How to add a new unit category
• How to add units to existing categories
• Testing requirements
• Code guidelines

License

ISC