Common conversions to remember
- 1 inch = 2.54 centimetres exactly
- 1 mile = 1.609344 kilometres
- 1 kilogram ≈ 2.2046 pounds
- 1 US gallon = 3.785 litres; 1 UK (imperial) gallon = 4.546 litres
- 0°C = 32°F; 100°C = 212°F; 0 K = −273.15°C
US vs UK gallons and cups
The US and UK gallon are different sizes, which causes real confusion with fuel economy (mpg). This tool lists both so you can pick the right one. US cups here are the legal US cup of 236.588 ml.
Temperature is different
Temperature scales have different zero points, so converting is not just multiplying. Fahrenheit = Celsius × 9/5 + 32. Kelvin = Celsius + 273.15.
Frequently asked questions
How precise is it?
Conversion factors are the exact or internationally accepted values and results show up to 8 significant decimals.
Why do some results show many digits?
Small units like millimetres produce large numbers. Use the table to pick the unit that suits you.
Can I swap from and to?
Yes, press the swap button.