Unit Converter
Free to use. Runs in your browser: your files and text are not uploaded.
Type a value, choose its unit, and see it converted into every other unit of the same kind at once.
How to use it
- Type the value.
- Choose the unit it is in. Units are grouped as length, weight, volume and temperature.
- Read the results. They update as you type.
Common conversions
| From | To | Multiply by |
|---|---|---|
| inches | centimetres | 2.54 |
| feet | metres | 0.3048 |
| miles | kilometres | 1.609344 |
| pounds | kilograms | 0.45359237 |
| ounces | grams | 28.3495 |
| US fluid ounces | millilitres | 29.5735 |
| US gallons | litres | 3.785411784 |
To go the other way, divide by the same number.
Temperature
Temperature scales have different zero points, so they need a formula, not one multiplier:
- °F = °C × 9 ÷ 5 + 32
- °C = (°F − 32) × 5 ÷ 9
- K = °C + 273.15
Water freezes at 0 °C, 32 °F and 273.15 K.
Where the numbers come from
The inch has been defined as exactly 2.54 cm, and the pound as exactly 0.45359237 kg, since an international agreement in 1959. The foot, yard and mile follow from the inch. The US gallon is defined as 231 cubic inches.
Limits
- Results are rounded to 6 decimal places.
- Volume units for cooking are the US ones. UK and metric cups and spoons are different sizes.
- The ounce here is the everyday (avoirdupois) ounce, not the troy ounce used for gold and silver.
Frequently asked questions
How many centimetres are in an inch?
Exactly 2.54. To convert centimetres to inches, divide by 2.54. For example, 10 cm is 3.937 inches.
How do I convert Celsius to Fahrenheit?
Multiply by 9, divide by 5, then add 32. So 100 °C is 212 °F, and 37 °C is 98.6 °F.
Why are there US and UK gallons?
They are different sizes. A US gallon is 3.785 litres and a UK (imperial) gallon is 4.546 litres. US cups, pints and fluid ounces also differ from the UK ones.