Units
Pressure converter
Bar to psi, atmospheres to kilopascals, millimetres of mercury. For tyres, for weather and for blood pressure.
Conversions are worked out on your own machine. No sign-up, no waiting and nothing sent anywhere.
Common conversions
| bar | pound per square inch |
|---|---|
| 1 bar | 14.504 psi |
| 2 bar | 29.008 psi |
| 5 bar | 72.519 psi |
| 10 bar | 145.038 psi |
| 20 bar | 290.075 psi |
| 50 bar | 725.189 psi |
| 100 bar | 1,450.38 psi |
| pound per square inch | bar |
|---|---|
| 1 psi | 0.068948 bar |
| 2 psi | 0.137895 bar |
| 5 psi | 0.344738 bar |
| 10 psi | 0.689476 bar |
| 20 psi | 1.379 bar |
| 50 psi | 3.4474 bar |
| 100 psi | 6.8948 bar |
| atmosphere | kilopascal |
|---|---|
| 1 atm | 101.325 kPa |
| 2 atm | 202.65 kPa |
| 5 atm | 506.625 kPa |
| 10 atm | 1,013.25 kPa |
| 20 atm | 2,026.5 kPa |
| 50 atm | 5,066.25 kPa |
| 100 atm | 10,132.5 kPa |
| millimetre of mercury | kilopascal |
|---|---|
| 1 mmHg | 0.133322 kPa |
| 2 mmHg | 0.266645 kPa |
| 5 mmHg | 0.666612 kPa |
| 10 mmHg | 1.3332 kPa |
| 20 mmHg | 2.6664 kPa |
| 50 mmHg | 6.6661 kPa |
| 100 mmHg | 13.332 kPa |
| kilopascal | pound per square inch |
|---|---|
| 1 kPa | 0.145038 psi |
| 2 kPa | 0.290075 psi |
| 5 kPa | 0.725189 psi |
| 10 kPa | 1.4504 psi |
| 20 kPa | 2.9008 psi |
| 50 kPa | 7.2519 psi |
| 100 kPa | 14.504 psi |
Worked out with the same factors the converter above uses.
The SI unit is the pascal, one newton per square metre. The practical problem is that it is tiny: ordinary atmospheric pressure is 101,325 pascals, so real life almost never uses it plain — it uses hectopascals (weather) or kilopascals (engineering).
The most-searched conversion is bar to psi, and it comes from tyres: Europe marks pressure in bar and the United States in psi. One bar is 14.5 psi, so a car's typical 2.2 bar is about 32 psi. The psi also has a definition that is satisfying to check: it is the pressure of one pound-force on one square inch, which works out to 6,894.76 pascals.
Medicine and meteorology keep the millimetre of mercury alive, which measures pressure by the height of a mercury column it would hold up. A blood pressure of “120/80” is in mmHg. The atmosphere is a reference unit defined as exactly 101,325 Pa, and its relationship to the torr is just as clean: one atmosphere is exactly 760 torr.
Every unit in this category
Frequently asked questions
How many psi are in a bar?
14.5038 psi. For tyres, 14.5 will do: 2 bar is 29 psi and 2.5 bar is 36.3 psi.
What is standard atmospheric pressure?
Exactly 101,325 pascals, which is 1,013.25 hectopascals, 1.01325 bar or 14.7 psi. That is the reference value at sea level.
Why is blood pressure measured in millimetres of mercury?
An inheritance from the instrument: early sphygmomanometers literally measured how high the blood pressure pushed a mercury column. The unit stuck even though the devices no longer contain mercury.