Pressure Converter
Convert between pascals, kilopascals, bar, psi, atmospheres and torr.
The pressure converter changes pressure readings between units. It is useful for tyre pressure, gas cylinders, weather reports, vacuum systems and engineering calculations, where different countries and industries use different units.
How to use the converter
- Enter the pressure value.
- Choose the from and to units.
- Read the converted value and the full table.
- Common use: converting tyre pressure between bar and psi.
How the conversion works
Result = value in pascals ÷ factor of the target unit
Worked example
2 bar to psi
2 × 100,000 = 200,000 Pa ÷ 6,894.757 = 29.01 psi
The same pressure is about 1.97 atmospheres or 1,500 torr.
Popular conversions
Jump straight to a single conversion, or use the converter above for any pair.
Who should use this pressure converter
- Drivers and riders checking tyre pressure, where the handbook is in psi and the pump gauge is in bar.
- Anyone reading a weather report where pressure is given in hectopascals or millibars rather than the unit on their device.
- Divers, plumbers and gas users working with cylinders where pressure determines safety and capacity.
- Engineering and science students converting between SI and imperial pressure units for calculations.
Common mistakes to avoid
- Treating bar and atmosphere as identical. One atmosphere is 1.01325 bar. Close enough for a rough check, but not for calculations that accumulate over many steps.
- Confusing gauge pressure with absolute pressure. A tyre gauge reads pressure above atmospheric. Absolute pressure adds roughly 1 bar to whatever the gauge shows.
- Checking tyre pressure when the tyres are warm. Driving raises pressure by 0.2–0.3 bar. Always measure cold, or you will under-inflate.
- Assuming psi and kPa differ by a neat factor. One psi is 6.895 kPa, not 7 or 6.9 repeating. Rounding to 7 introduces a 1.5% error.
- Forgetting that weather pressure is absolute. A reading of 1013 hPa is absolute pressure at sea level, not a gauge reading, so it never starts at zero.
Gauge pressure versus absolute pressure
Most everyday pressure readings are gauge readings. When a tyre gauge shows 32 psi, it means 32 psi above the surrounding atmosphere, not 32 psi above a vacuum. Absolute pressure is the real physical pressure, and it equals gauge pressure plus atmospheric pressure of about 14.7 psi or 1.013 bar.
This distinction matters in different places. Tyre and gas cylinder checks use gauge readings, because that is what the gauge shows. Weather reports, diving tables and scientific work use absolute pressure, because physics depends on the total force. Confusing the two produces errors of roughly one atmosphere, which is a serious mistake in diving and only mildly annoying in a bicycle tyre.
Pressure units explained
- Pascal
- One newton per square metre. The SI unit, and a very small one — a car tyre is about 220,000 pascals.
- Bar
- 100,000 pascals, or roughly the atmospheric pressure at sea level. Common for tyres and gases in many countries.
- PSI
- Pounds per square inch. The tyre pressure unit in the US and UK.
- Atmosphere
- Standard atmospheric pressure at sea level, equal to 101,325 pascals or 14.696 psi.
- Torr
- Millimetres of mercury, used for vacuum measurements and blood pressure in some countries.
Tyre pressures and everyday anchors
A typical car tyre at 32 psi is about 2.2 bar or 220 kPa. Bicycle tyres run much higher, from 80 to 100 psi for road bikes, which is 5.5 to 6.9 bar. Truck and bus tyres often sit near 100 psi or 7 bar. A gas cylinder marked at 14.7 psi is holding exactly one atmosphere of gauge pressure.
Two practical points. Tyre pressures are always quoted cold, because a few kilometres of driving raises them by 0.2–0.3 bar. And a slow leak of half a bar is easy to miss by eye but noticeable in fuel consumption and tyre wear, which is why checking monthly is worth the two minutes.
Frequently asked questions
How do I convert bar to psi?
Multiply bar by 14.5038. So 2 bar is about 29 psi, and 32 psi (a common car tyre pressure) is about 2.2 bar.
What is standard atmospheric pressure?
Standard atmospheric pressure is 101,325 pascals, which is 1 atm, 1.01325 bar, 14.696 psi or 760 torr at sea level.
What is the difference between bar and atm?
They are close but not identical: 1 atm equals 1.01325 bar. For everyday tyre and gas pressure checks the difference is small enough to ignore.