Unit converter
Switch between metric and imperial for length, weight, temperature, and more.
How unit conversion works
Every unit in a category is defined relative to one base unit. To convert, the calculator turns your value into the base unit, then into the unit you want. Length uses metres, weight uses kilograms, and so on. Temperature is special because the scales do not share a zero, so it converts through Celsius using its own formulas.
Handy conversions
- 1 inch = 2.54 cm, 1 mile = 1.609 km, 1 foot = 0.3048 m
- 1 kg = 2.205 lb, 1 ounce = 28.35 g
- Celsius to Fahrenheit: F = C × 9/5 + 32
The tool covers length, weight, temperature, volume, area, speed, data size, and time. Use the swap button to flip the two units instantly.
Frequently asked questions
How do I convert between units?
Pick a category, choose the unit you are converting from and to, and type a value. The result updates instantly, and the swap button reverses the direction.
How many centimetres are in an inch?
Exactly 2.54 centimetres. So 10 inches is 25.4 cm. Choose Length, then inches to centimetres, to convert any value.
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. For example, 20°C is 68°F. Select the Temperature category to convert between Celsius, Fahrenheit, and Kelvin.
What units can I convert?
Length, weight and mass, temperature, volume, area, speed, data size, and time, each with the common metric and imperial units.
How accurate are the conversions?
They use standard internationally defined factors, so results are accurate to several decimal places, more than enough for everyday and most technical use.