Unit Converter
Convert between units of length, weight, temperature, and more. Runs on your device — nothing is uploaded, nothing is stored.
Convert between length units
Common conversion examples
Length
1 meter = 3.281 feet
1 kilometer = 0.621 miles
Weight
1 kilogram = 2.205 pounds
1 pound = 0.454 kilograms
Temperature
0°C = 32°F
100°C = 212°F
Area
1 square meter = 10.764 square feet
1 acre = 4,047 square meters
Volume
1 liter = 0.264 gallons
1 gallon = 3.785 liters
Speed
1 m/s = 3.6 km/h
1 mph = 1.609 km/h
This unit converter handles six groups of everyday measurements: length (millimetres, centimetres, metres, kilometres, inches, feet, yards, miles), weight (milligrams, grams, kilograms, ounces, pounds, stone, metric and US tons), temperature (Celsius, Fahrenheit, Kelvin), area (square millimetres up to square kilometres, square inches, feet and yards, acres, hectares), volume (millilitres, litres, cubic metres, US fluid ounces, cups, pints, quarts, gallons, cubic inches and feet) and speed (m/s, km/h, mph, ft/s, knots).
Pick a group, choose the From and To units, and type a number into the value box. The result appears as you type, with the working underneath: the value multiplied into a base unit, then divided into the target unit, plus a one-line rate such as 1 km = 0.621371 mi. The swap button flips the two units and their values, and a short list of common conversions sits below for a quick sanity check. Temperature uses the proper offset formulas through Celsius rather than a simple multiplier.
Why this runs on your device
There is no privacy angle worth inventing here — a number and two unit names are not sensitive. What running in the page does give you is speed: the answer updates on every keystroke with no round trip, and there is nothing to sign up for.
- Choose a group: Length, Weight, Temperature, Area, Volume or Speed.
- Select the From and To units from the two menus.
- Type a number into the value box; the converted result appears straight away.
- Press the swap button to reverse the conversion, or read the working underneath to check the arithmetic.
- Only the six groups above. There is no currency, time, data size, pressure, energy or fuel economy conversion.
- Liquid volumes are US units only (US cup, pint, quart, gallon and fluid ounce). Imperial pints and gallons are not offered, so a UK recipe or fuel figure needs converting separately.
- Results are rounded to six decimal places, so a very small amount can show as 0. Some factors, including ounce, pound, stone, acre and km/h, are stored to roughly six significant figures, which is plenty for everyday use but not for scientific work.
- You type into the From box only; the converted value is read-only. To go the other way, use the swap button.