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Pressure converter

psi, bar, kPa, hPa/mbar, atmospheres, mmHg, torr, inHg and kgf/cm², for tyres, weather, blood pressure and engineering.

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Frompound per square inch (psi)
1
Tobar (bar)
0.06894757293
DecimalsAuto (up to 10 significant digits)

Formula: bar = psi × 0.0689475729317

1 psi = 0.06894757293 bar

Common values: pound per square inch to bar

psibar
1 psi0.06894757293 bar
5 psi0.3447378647 bar
10 psi0.6894757293 bar
15 psi1.034213594 bar
20 psi1.378951459 bar
30 psi2.068427188 bar
32 psi2.206322334 bar
35 psi2.413165053 bar
40 psi2.757902917 bar
50 psi3.447378647 bar
100 psi6.894757293 bar

How it works

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.

Common pressure conversions

Tyre pressures are given in psi or bar (1 bar ≈ 14.5 psi), weather pressure in hectopascals or inches of mercury, and blood pressure in millimetres of mercury.

  • 1 psi = 0.06894757293 bar (bar = psi × 0.0689475729317)
  • 1 bar = 14.50377377 psi (psi = bar × 14.503773773)
  • 1 atm = 101.325 kPa (kPa = atm × 101.325)
  • 1 mmHg = 0.1333223874 kPa (kPa = mmHg × 0.133322387415)
  • 1 inHg = 33.8638864 hPa (hPa = inHg × 33.8638864034)
  • 1 kPa = 0.1450377377 psi (psi = kPa × 0.14503773773)

Every pressure unit in this converter

The size of each unit in pascals (Pa), the base unit the converter uses internally. Values are exact where the unit has an exact definition.

UnitIn PaSystem
pascal (Pa)1 PaSI
hectopascal (hPa)100 PaSI
kilopascal (kPa)1,000 PaSI
megapascal (MPa)1,000,000 PaSI
bar (bar)100,000 PaOther metric
millibar (mbar)100 PaOther metric
standard atmosphere (atm)101,325 PaOther metric
technical atmosphere (kgf/cm²) (kgf/cm²)98,066.5 PaOther metric
pound per square inch (psi)6,894.757293 PaImperial / US
millimetre of mercury (mmHg)133.3223874 PaMercury
torr (Torr)133.3223684 PaMercury
inch of mercury (inHg)3,386.38864 PaMercury

How to use it

  1. Pick the unit on your gauge or document and the unit you need.
  2. Type the pressure in either box.
  3. 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.

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