How to use the Pressure Converter
- Type the pressure you want to convert.
- Choose the unit you are converting from.
- Choose the unit you want.
- Read the result and the rate, and use the reference table below for common values.
Formula used
Result = Value × (pascals per source unit ÷ pascals per target unit). 1 atm = 101,325 Pa, 1 bar = 100,000 Pa, 1 psi = 6,894.757 Pa, 1 mmHg = 133.322 Pa.
Worked example
Here is the Pressure Converter worked through with the example values shown above, so you can check each step by hand.
| Inputs | |
|---|---|
| Value | 32 |
| From | Pounds per square inch (psi) |
| To | Bar |
| Result | |
| Converted value | 2.2063223 |
| Conversion rate | 1 psi = 0.068947573 bar |
Quick reference table
Common values converted with the units selected above.
| From | To |
|---|---|
| 1 psi | 0.068947573 bar |
| 10 psi | 0.68947573 bar |
| 32 psi | 2.2063223 bar |
| 50 psi | 3.4473786 bar |
| 100 psi | 6.8947573 bar |
| 1,000 psi | 68.947573 bar |
The units and how they relate
The SI unit is the pascal (Pa), one newton per square metre. It is tiny, so kilopascals (kPa) and megapascals (MPa) are common. One bar is exactly 100,000 Pa, a millibar is a hundredth of that, and standard atmospheric pressure is defined as 101,325 Pa, which is 1 atmosphere.
In everyday terms 1 atm is 1.01325 bar, 14.695949 psi, 759.999892 mmHg and 29.921256 inHg. One psi is 6.894757 kPa.
Common conversions
A car tyre at 32 psi is 2.206322 bar or 220.632233 kPa. A reading of 2.2 bar is 31.908302 psi. Normal sea-level air pressure of 1,013.25 millibars is 29.921256 inHg, which is the figure US weather reports quote.
A blood pressure of 120 mmHg is 15.998686 kPa, the unit used in some countries. Diving depth adds roughly 1 bar for every 10 metres of seawater, so a diver at 30 metres feels about 4 bar in total including the air above.
Gauge pressure and absolute pressure
Tyre and boiler gauges usually show gauge pressure, which is measured above the surrounding air pressure. Absolute pressure includes the atmosphere, so absolute = gauge + about 14.7 psi (1.013 bar) at sea level. A flat tyre reads 0 psi gauge but is still at atmospheric pressure.
This converter changes units only and treats your value as it is. If a formula needs absolute pressure, add atmospheric pressure to a gauge reading first.
Torr, mmHg and inches of mercury
The torr is defined as exactly 1/760 of a standard atmosphere, while the millimetre of mercury is defined from the density of mercury, so the two differ by less than one part in seven million. For nearly everything, treat them as equal.
Inches of mercury is used in aviation and US weather. Altimeter settings are quoted this way, for example 29.92 inHg for standard pressure.
Frequently asked questions
How do I convert psi to bar?
Divide by 14.5038, or multiply by 0.0689476. For example, 32 psi is 2.206322 bar.
How many kPa is 1 psi?
1 psi is 6.894757 kPa.
What is standard atmospheric pressure?
101,325 pascals, which is 1 atm, 1.01325 bar, 14.696 psi or 760 mmHg.
Is a torr the same as mmHg?
Almost exactly. They differ by less than one part in seven million, so they are interchangeable in practice.
What is the difference between gauge and absolute pressure?
Gauge pressure is measured relative to the air around you. Absolute pressure is measured relative to a vacuum, so it is gauge plus atmospheric pressure.
What tyre pressure should I use?
Use the figure on the vehicle’s placard or in the manual, in the unit your gauge shows. This converter helps when the gauge and the manual use different units.
This calculator gives estimates for information only. Actual figures from a bank, employer, tax authority or doctor may differ. It is not financial, tax, legal or medical advice.