Unit Converter
Convert length, weight, temperature, speed, area, volume and data - pick a category, choose your units and the answer updates as you type.
One converter, seven measurement families
Most conversions are a single multiplication. Every unit in a category is stored as a factor relative to one base unit - metres for length, grams for weight, litres for volume - so converting means turning your value into the base unit and then out again into the target unit. Change the category, from-unit, to-unit or value and the result recalculates instantly. The swap button flips the two units, which is handy for checking a conversion in both directions.
Temperature is the exception
Celsius, Fahrenheit and Kelvin do not line up at zero, so they need formulas rather than a
simple factor. Celsius to Fahrenheit is C x 9/5 + 32; Celsius to Kelvin is
C + 273.15. That is why 0C, 32F and 273.15K all describe the same freezing point
of water, and why this tool treats temperature as a special case behind the scenes.
Handy conversions to remember
| From | Equals |
|---|---|
| 1 inch | 2.54 cm |
| 1 mile | 1.609 km |
| 1 kilogram | 2.205 lb |
| 1 litre | 0.264 US gal |
| 100 km/h | 62.14 mph |
| 1 hectare | 2.471 acres |
| 1 GB | 0.931 GiB |
Metric, imperial and the traps between them
A lot of conversion errors come from units that share a name but not a size. The US and UK gallon differ by about 20 percent, US and UK fluid ounces are slightly different again, and a US pint is 16 fluid ounces against the UK pint's 20. Weight has its own trap: an ounce of mass is not a fluid ounce of volume, even though both are shortened to "oz" in recipes. Data sizes are the modern version of the same confusion, with drive makers counting in decimal gigabytes while your operating system counts in binary gibibytes. Wherever a unit is ambiguous, this converter spells out the system in the dropdown so you are never guessing which one you picked. Values are computed to full precision and only rounded for display, so chaining conversions does not accumulate error.
Need just one family with more detail? Try the dedicated length converter, temperature converter or data size converter. Converting money instead? The currency converter uses live exchange rates.