What this converter does
This converter turns pressure between bar, psi, megapascals, kilopascals, atmospheres, millimetres of mercury and millibars — instantly and with exact factors. Type a value, pick the units, and the answer updates as you type. Handy for tyres, hydraulics and process gauges.
One bar is exactly 100,000 pascals and equals about 14.504 psi. Bar is close to one atmosphere but not identical (1 atm = 1.01325 bar). For very small pressures, see the mmHg option, common in vacuum and medical work.
The units it covers
Every unit measures pressure, so each converts through the pascal with a fixed ratio.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Bar | bar | 100000 | Tyres, hydraulics, weather |
| Pound per square inch | psi | 6894.76 | US pressure, tyres, tanks |
| Megapascal | MPa | 1000000 | Materials, high pressure |
| Kilopascal | kPa | 1000 | SI everyday pressure |
| Atmosphere | atm | 101325 | Reference standard pressure |
| Millimetre of mercury | mmHg | 133.322 | Vacuum, blood pressure |
| Millibar | mbar | 100 | Meteorology, low pressure |
The formula
Each unit has a fixed value in pascals, so any conversion goes through the pascal once:
result = value × factor_from ÷ factor_toWhere:
- value = the number you typed, in the “from” unit
- factor_from = the “from” unit’s value in pascals
- factor_to = the “to” unit’s value in pascals
Worked example
Convert 2 bar to psi.
bar = 100000 Pa · psi = 6894.757 Pa2 × 100000 ÷ 6894.757 = 29.008 psiSo 2 bar is about 29 psi — a typical car-tyre pressure.
The units in this example
A metric pressure unit equal to exactly 100,000 pascals, close to one atmosphere. Common for tyres, hydraulics and weather.
- 1 bar = 100,000 Pa
- 1 bar ≈ 14.504 psi
- 1 bar = 100 kPa
- 1 bar ≈ 0.987 atm
An imperial pressure unit — one pound-force per square inch. Standard for US tyres, tanks and pneumatic systems.
- 1 psi ≈ 6894.76 Pa
- 1 psi ≈ 0.06895 bar
- 1 psi ≈ 6.895 kPa
- 14.504 psi = 1 bar