Pressure Converter

Pick any two pressure units and type in either box. The pascal-based units and psi are exact; the mercury units use their conventional definitions.

32 psi = 2.2063223338 bar

Where each unit is used

  • psi — tire, compressor and hydraulic pressures in the US and UK.
  • bar and kPa — tire and pump pressures in Europe, Canada and Australia; 1 bar = 100 kPa.
  • hPa / mbar — weather maps and forecasts; they are the same size (1 hPa = 1 mbar).
  • inHg — barometric pressure in US weather reports and aviation altimeter settings (29.92 inHg is standard).
  • atm — chemistry and diving; exactly 101,325 Pa.

Gauge vs absolute pressure

Tire gauges read pressure above the surrounding air (gauge pressure, sometimes written psig or barg). Absolute pressure adds the atmosphere on top: a tire at 32 psi gauge is at about 46.7 psi absolute at sea level. The conversion factors are the same for both, but don’t mix the two kinds when comparing numbers.

Units in pascals

Pressure units expressed in pascals
UnitIn pascals
1 hectopascal (hPa)100 Pa
1 kilopascal (kPa)1,000 Pa
1 megapascal (MPa)1,000,000 Pa
1 bar (bar)100,000 Pa
1 millibar (mbar)100 Pa
1 standard atmosphere (atm)101,325 Pa
1 pound per square inch (psi)6,894.75729317 Pa
1 millimeter of mercury (mmHg)133.322387415 Pa
1 inch of mercury (inHg)3,386.389 Pa

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