About the Unit Converter
Convert between metric and imperial units across ten quantities: length, weight, temperature, volume, area, speed, digital storage, time, pressure and energy. See the result in every unit at once.
Key features
- 10 quantities: length, weight, temperature, volume, area, speed, data, time, pressure and energy
- Over 75 metric, imperial and US customary units
- Swap units with one click
- Conversion table of every unit at a glance
- Exact conversion factors (1 in = 2.54 cm, 1 lb = 0.45359237 kg)
- Works offline once loaded, with no sign-up
Convert any unit in one place
This all-in-one unit converter covers the measurements you deal with every day: cooking, travel, fitness, DIY, science homework and engineering. Pick a quantity, choose two units and type a value; the result and a table of every other unit update instantly.
Supported quantities
| Quantity | Example units | Dedicated page |
|---|---|---|
| Length | mm, cm, m, km, in, ft, yd, mi, nmi | Length Converter |
| Weight / mass | mg, g, kg, t, oz, lb, st, US ton | Weight Converter |
| Temperature | °C, °F, K | Temperature Converter |
| Volume | ml, l, m³, tsp, tbsp, fl oz, cup, pint, quart, gallon | Volume Converter |
| Area | cm², m², km², in², ft², yd², acre, hectare, mi² | Area Converter |
| Speed | m/s, km/h, mph, knot, ft/s | Speed Converter |
| Digital storage | bit, byte, kB–TB, KiB–TiB | Data Storage Converter |
| Time | ms, s, min, h, day, week, year | Time Converter |
| Pressure | Pa, kPa, bar, psi, atm, mmHg | Pressure Converter |
| Energy | J, kJ, cal, kcal, Wh, kWh, BTU | Energy Converter |
How conversions work
Every unit (except temperature) is stored as a factor relative to a base SI unit. A conversion is:
result = value × factor(from) ÷ factor(to)
For example, 5 miles to kilometers: 5 × 1609.344 m ÷ 1000 m = 8.04672 km.
Metric vs imperial
The metric system (SI) is used by almost every country and in science. The imperial and US customary systems are still common in the United States, and the UK still uses some imperial units (miles, pints, stones). Remember that some units share a name but differ in size, such as the US and UK gallon or fluid ounce.
Related calculators
For other everyday math, try the Percentage Calculator or the Scientific Calculator.
How to use the Unit Converter
- Enter your numbers in the fields above. Units and options can be changed at any time.
- The result updates instantly as you type; there's no calculate button to press.
- Check the breakdown under the main result for the details behind the number.
- Adjust the inputs to compare scenarios, for example a different rate or term.