Unit Converter
Convert length, weight, area, volume, temperature, speed and more. The result appears as you type.
Calculation details and equivalent units
| Millimetre (mm) | 1000 |
|---|---|
| Centimetre (cm) | 100 |
| Metre (m) | 1 |
| Kilometre (km) | 0.001 |
| Inch (in) | 39.3700787402 |
| International foot (ft) | 3.28083989501 |
| Yard (yd) | 1.09361329834 |
| International mile (mi) | 0.000621371192237 |
The result multiplies by the source factor and divides by the target factor. Display rounding does not change that calculation.
US gallons, UK gallons, short tons, metric tonnes, and long tons are separate units. Temperature uses an offset.
How to use it
- Choose the kind of measurement, such as length, mass or temperature.
- Enter the value, then choose the unit to convert from and the unit to convert to.
- Read the result, then copy it alone or with its unit.
Examples
- Inches to centimetres1 in 2.54 cm
- Kilograms to pounds1 kg 2.20462262185 lb
- Celsius to Fahrenheit37 °C 98.6 °F
- Miles to kilometres1 mi 1.609344 km
Tool details and privacy
Convert a value between units of length, mass, area, volume, temperature, speed, energy, pressure, time and power. The result appears as you type, with a table of equivalent units.
Units that share a name are kept apart: US and UK gallons, and metric tonnes, US short tons and UK long tons.
Options
- Display precision: automatic, or 0 to 8 decimal places.
- A button swaps the two units.
- Search for a unit by name or abbreviation.
Limits
- The value can be up to 1,000,000,000,000,000, positive or negative.
- Digits can be typed as 123 or ١٢٣, and a decimal comma such as 1,5 is accepted. A number whose comma could mean thousands or decimals, such as 1,250, is rejected.
- Automatic precision shows up to 12 significant digits.
- This is a general-purpose converter, not a substitute for specialist measurement or instrument calibration.
Privacy
The conversion runs in your browser and the value is not sent to the server. If JavaScript is switched off, the form sends the value to the server to be converted. The browser remembers only the last measurement type, the two units and the display precision.
Questions
How many centimetres are in an inch?
One inch is exactly 2.54 centimetres. Enter the number of inches and convert from inches to centimetres.
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 and add 32. For example, 37 °C is 98.6 °F.
What is the difference between a US gallon and a UK gallon?
A US liquid gallon is 3.785411784 litres and a UK gallon is 4.54609 litres. Choose the right one from the list.
Where do the conversion factors come from?
The linear factors follow NIST SP 811, the guide to SI unit conversions.