Pressure converter
psi, bar, kPa, hPa/mbar, atmospheres, mmHg, torr, inHg and kgf/cm², for tyres, weather, blood pressure and engineering.
Loading tool…
Pressure has more everyday units than most quantities. Tyre gauges read psi or bar (a car door sticker saying 35 psi means about 2.41 bar or 241 kPa); weather maps use hectopascals, which are the same as millibars (standard sea-level pressure is 1013.25 hPa); US weather reports use inches of mercury; blood pressure is measured in millimetres of mercury; pressure-cooker and compressor specs use bar, kPa or kgf/cm².
The SI unit is the pascal (1 N/m²). The other units are defined from it: 1 bar = 100,000 Pa exactly; 1 standard atmosphere = 101,325 Pa exactly; 1 torr = 1/760 atm; 1 psi = 1 pound-force per square inch = 6894.757 Pa (derived from the exact pound, inch and standard gravity); the conventional millimetre of mercury is 133.322387415 Pa; 1 kgf/cm² = 98,066.5 Pa. Sources: NIST Special Publication 811 (Guide for the Use of the SI), Appendix B.
Gauge pressure (what a tyre gauge shows) is measured above atmospheric pressure, while absolute pressure includes it. The converter does not add or remove the atmosphere, so keep both values in the same reference.
How to use it
- Pick the unit on your gauge or document and the unit you need.
- Type the pressure in either box.
- Use the table for common tyre and weather values.
Frequently asked questions
How many psi is 1 bar?
1 bar = 14.5038 psi, and 1 psi = 0.0689476 bar. A tyre at 2.2 bar is at about 32 psi.
Are hPa and mbar the same?
Yes. One hectopascal equals one millibar (100 Pa). Meteorologists switched to the hectopascal name so the numbers stayed the same.
Is mmHg the same as torr?
Almost. 1 torr is exactly 1/760 of a standard atmosphere (133.3224 Pa); the conventional mmHg is 133.322387415 Pa. The difference is less than 0.000015%, irrelevant for blood pressure or vacuum gauges.
What is standard atmospheric pressure in different units?
101,325 Pa = 1013.25 hPa = 1.01325 bar = 14.696 psi = 760 mmHg = 29.92 inHg.
Related tools
- Unit converterConvert length, weight, area, volume, temperature, speed, pressure, energy, power, data, fuel economy and time with exact factors.
- Temperature converterCelsius, Fahrenheit, Kelvin and Rankine, converted with the exact offset formulas and a common-values table.
- Energy converterJoules, kilojoules, calories and kilocalories, watt-hours and kWh, BTU, foot-pounds and electronvolts.
- Power converterWatts, kilowatts, megawatts, mechanical and metric horsepower, BTU per hour, kcal per hour and tons of refrigeration.
- Weight converter (mass)Kilograms, pounds, ounces, stone, grams, tonnes, short and long tons, troy ounces and carats, converted both ways.