About this tool
Convert between metric and imperial units in one place: centimetres to inches, kilograms to pounds, Celsius to Fahrenheit, square metres to square feet, litres to gallons, km/h to mph and more. Results update as you type and use exact international definitions.
How to use it
- Choose what you're measuring: length, weight, temperature, area, volume or speed.
- Enter a value and pick the unit to convert from.
- Pick the unit to convert to — use ⇄ to swap them.
Good to know
- Uses exact definitions, e.g. 1 inch = 2.54 cm and 1 pound = 0.45359237 kg.
- Cups, fluid ounces and gallons are US units; the UK (imperial) gallon is listed separately.
- Results show up to eight significant digits.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. For example 25 °C × 9/5 + 32 = 77 °F. Choose Temperature above to convert instantly.
Is a US gallon the same as a UK gallon?
No. A US gallon is 3.785 litres, while a UK (imperial) gallon is 4.546 litres. Both are available in the Volume list.