Everyday conversions
| Example | From | To |
|---|---|---|
| Car tyre | 32 psi | 2.206322 bar |
| Blood pressure | 120 mmHg | 15.998686 kPa |
| Recipe | 1 US cup | 236.588237 mL |
| Speed limit | 100 km/h | 62.137119 mph |
| Food energy | 250 kcal | 1,046 kJ |
| Electricity | 1 kWh | 3,412.141633 BTU |
| Car engine | 150 hp | 111.854981 kW |
| A year | 1 year (365 days) | 8,760 hours |
Exact conversion factors
The converter works from the definitions, so results aren't rounded until they're shown (up to six decimals):
- Length and weight: 1 inch = 2.54 cm, 1 foot = 0.3048 m, 1 mile = 1,609.344 m, 1 pound = 0.45359237 kg.
- Volume: 1 US gallon = 231 cubic inches = 3.785411784 L (4 quarts, 8 pints, 16 cups, 128 fl oz); 1 imperial gallon = 4.54609 L (160 imperial fl oz).
- Pressure: 1 bar = 100,000 Pa; 1 atm = 101,325 Pa; 1 psi = one pound-force on a square inch = 6,894.757293 Pa; 1 mmHg = 133.322387 Pa; 1 torr = 1/760 atm.
- Energy and power: 1 kcal (food Calorie) = 4.184 kJ; 1 kWh = 3.6 MJ; 1 BTU = 1,055.05585262 J; 1 mechanical horsepower = 550 foot-pounds per second = 745.699872 W; 1 metric horsepower (PS) = 735.49875 W.
- Time: a day is 86,400 seconds; a year here is 365 days, and a month is a twelfth of that (about 30.42 days).
Factors match NIST Special Publication 811, Appendix B and the BIPM SI Brochure (checked 2 October 2026).
Indian units included
- Cent = 1/100 acre = 435.6 sq ft (common in Kerala, Tamil Nadu and Karnataka).
- Guntha = 1/40 acre = 1,089 sq ft (Maharashtra, Karnataka, Telangana).
- Gaj = 1 square yard = 9 sq ft (North India).
- Tola = 11.6638 g (gold and silver). Quintal = 100 kg (crops).
Bigha, kanal and marla vary from state to state, so they aren't included. Check the local definition with your land records office.