Unit converter
Convert instantly between metric and imperial units across six different quantities.
Unit converter: what it is and how it works
Converting units is essential when following a recipe from another country, comparing a car’s top speed, working out land area in acres or reading a forecast in Fahrenheit. This unit converter brings the most common quantities together in one tool: length, mass, area, volume, speed and temperature.
For the first five, conversion means multiplying by a fixed factor: a mile is exactly 1,609.344 metres and a pound is 0.45359237 kilograms. Temperature is different because the Celsius, Fahrenheit and Kelvin scales do not share the same zero, so specific formulas are used. Gallons, fluid ounces and cups are US measures, except the UK gallon, which is listed separately.
How to use it
- Choose the quantity: length, mass, area, volume, speed or temperature.
- Enter the value and select the units to convert from and to.
- Read the result and the conversion factor.
Converted value = value × source factor ÷ target factor · °F = °C × 9/5 + 32Worked example
10 kilometres is 6.2137 miles. 100 °F equals 37.78 °C. A US gallon is 3.785 litres and an acre is 0.4047 hectares.
Frequently asked questions
How do I convert Fahrenheit to Celsius?
Subtract 32 and multiply by 5/9. For example, 100 °F − 32 = 68; 68 × 5/9 = 37.78 °C.
How many kilometres in a mile?
A statute mile is 1.609344 km. A nautical mile is 1.852 km.
How many kilos in a pound?
One pound is 0.45359237 kg, about 454 grams.
Is a US gallon the same as a UK gallon?
No. A US gallon is 3.785 litres and a UK (imperial) gallon is 4.546 litres.