Free Online Unit Converter

UnitWise converts measurements instantly — lengths, weights, temperatures, volumes, speeds and more. Type a number, pick your units, and get the answer. No sign-up, no download, everything runs in your browser.

Convert units

Category
Value
From
To

Browse by category

LengthConvert between metric and imperial lengths — from millimeters to miles.Mass / WeightConvert weights and masses — grams, kilograms, pounds, ounces and stone.TemperatureConvert Celsius, Fahrenheit and Kelvin, with the formulas explained.VolumeConvert liquid and dry volumes — liters, gallons, cups, pints and more.AreaConvert land and surface areas — square meters, acres, hectares and more.SpeedConvert speeds — km/h, mph, knots and meters per second.TimeConvert time units — seconds, minutes, hours, days, weeks and years.PressureConvert pressures — pascal, bar, PSI and atmospheres.EnergyConvert energy — joules, calories and kilowatt-hours.PowerConvert power — watts, kilowatts and horsepower.Data StorageConvert data sizes — bytes, kilobytes, megabytes, gigabytes and binary units.

Popular conversions

Millimeter to InchLength Centimeter to FootLength Centimeter to InchLength Inch to CentimeterLength Foot to CentimeterLength Mile to KilometerLength Kilometer to MileLength Meter to FootLength Foot to MeterLength Yard to MeterLength Pound to KilogramMass / Weight Kilogram to PoundMass / Weight Ounce to GramMass / Weight Gram to OunceMass / Weight Stone to KilogramMass / Weight Kilogram to StoneMass / Weight Milliliter to Fluid ounceVolume Fluid ounce to MilliliterVolume Liter to GallonVolume Gallon to LiterVolume Cup to MilliliterVolume Square meter to Square footArea Square foot to Square meterArea Acre to HectareArea Miles per hour to Kilometers per hourSpeed Kilometers per hour to Miles per hourSpeed Knot to Miles per hourSpeed Celsius to FahrenheitTemperature Fahrenheit to CelsiusTemperature Celsius to KelvinTemperature Megabyte to GigabyteData Storage Gigabyte to MegabyteData Storage Kilobyte to MegabyteData Storage Minute to HourTime Hour to MinuteTime

How it works: every conversion uses standard published factors — for example, one inch is exactly 2.54 centimeters, and one pound is exactly 0.45359237 kilograms. Temperature conversions use the standard offset formulas.

From the blog

Metric vs imperial: why the world uses two systems
Celsius to Fahrenheit without a calculator
Pounds, kilograms and the story of the stone
Why sailors measure speed in knots
Megabyte vs mebibyte: why your drive looks smaller