Unit converter
Convert length, area, volume, mass, temperature, speed, time, energy, pressure and data size with exact factors.
| Unit | Value |
|---|---|
| millimetre (mm) | 1000 |
| centimetre (cm) | 100 |
| metre (m) | 1 |
| kilometre (km) | 0.001 |
| inch (in) | 39.370079 |
| foot (ft) | 3.28084 |
| yard (yd) | 1.093613 |
| mile (mi) | 0.000621 |
| nautical mile | 0.00054 |
About the conversion factors
Length, area, volume and mass factors are exact by definition (1 inch = 2.54 cm, 1 pound = 0.45359237 kg, 1 US gallon = 231 cubic inches = 3.785411784 L). Temperatures convert with offsets, not a single factor: °F = °C × 9/5 + 32 and K = °C + 273.15. The calorie is the thermochemical calorie (4.184 J), the BTU is the International Table BTU (1,055.05585262 J), and a year is taken as 365.25 days. Data sizes show both decimal units (1 kB = 1,000 bytes) and binary units (1 KiB = 1,024 bytes), because storage makers and operating systems use different ones.
Results show up to 10 significant figures. Need a whole calculation rather than a conversion? Browse the calculators by subject.