How to use it
Pick what you are converting, type a value, and choose the units to convert from and to. Press Swap units to turn the conversion around.
How it works
Every unit is stored as a multiple of one base unit (metres, kilograms, litres and so on). The value is turned into the base unit, then into the unit you want:
result = value × from-unit size ÷ to-unit size
Temperature is the one exception. Celsius, Fahrenheit and Kelvin have different zero points, so they use formulas instead of a single multiplier.
Useful exact values
| Conversion | Exact value |
|---|---|
| 1 inch | 2.54 cm |
| 1 foot | 30.48 cm |
| 1 mile | 1.609344 km |
| 1 pound | 0.45359237 kg |
| 1 US gallon | 3.785411784 L |
| 1 acre | 4,046.8564224 m² |
Common questions
Why are US and UK gallons different?
A US gallon is about 3.785 litres. A UK (imperial) gallon is about 4.546 litres. This tool uses US measures for gallons, quarts, cups and fluid ounces.
What is the difference between KB and KiB?
1 KB (kilobyte) is 1,000 bytes. 1 KiB (kibibyte) is 1,024 bytes. Storage makers use KB, MB and GB. Some operating systems show KiB and GiB but label them KB and GB. That is why a "1 TB" drive shows about 931 GB.
What is a hectare?
10,000 square metres, about the size of a football pitch and a half. Land in the Philippines is often sold by the square metre or by the hectare.
Last checked: 2026-09-25