Pressure Converter
Convert between pascals, bar, psi, atmospheres and mmHg.
What the Pressure Converter does
Pressure is force per unit area. The pascal is the SI unit but is small, so bar and kPa are used in practice. Car tyres are usually quoted in psi or bar; weather reports use hectopascals or millibars, which are equal.
Formula
Convert to pascal, then divide by the target unit's factorResult = Value × (from factor ÷ to factor)
Inputs explained
| Input | Unit | Required | Notes |
|---|---|---|---|
| Value | number | Yes | — |
| From | one of 9 options | Yes | — |
| To | one of 9 options | Yes | — |
How to use it
- Choose From and To.
- Enter Value.
- Select Calculate.
Worked example
Convert 2.2 bar of tyre pressure to psi.
- Value
- 2.2
- From
- Bar
- To
- psi
2.2 × 14.5038 = 31.91 psi.
Reading the result
- Standard atmospheric pressure is 101,325 Pa, which is 1 atm, 1.01325 bar, 14.696 psi or 760 torr.
- One hectopascal and one millibar are identical, which is why weather charts can use either without changing the numbers.
Common mistakes
- Confusing gauge pressure with absolute pressure. A tyre reading 32 psi on a gauge is about 46.7 psi absolute, because the gauge reads zero at atmospheric pressure.
- Treating bar and atmospheres as interchangeable. They differ by about 1.3%.
Frequently asked questions
What is standard atmospheric pressure?
101,325 Pa, which equals 1.01325 bar, 14.696 psi or 760 mmHg at sea level.