🎈 Pressure

Pressure Converter

Tyre pressure in PSI, weather pressure in hPa, hydraulics in bar — convert all of them. Enter your number and press Convert.

Written and reviewed by SM Arijul Islam · Last reviewed 28 October 2026 · Editorial standards · Report an error

About the pressure converter

Pressure is force per unit area, measured in pascals in the SI system. Because it is used in so many trades, dozens of units survive in daily life. This converter treats every value as gauge-style pressure — no atmospheric offset is applied.

Exact and standard factors

1 bar = 100,000 Pa exactly
1 atmosphere = 101,325 Pa exactly
1 PSI = 6,894.757293168 Pa
1 torr = 1 mmHg = 133.322 Pa
1 kg/cm² = 98,066.5 Pa · 1 inHg = 3,386.389 Pa

Typical car tyre pressure is 32 PSI ≈ 2.2 bar ≈ 220 kPa.

How to convert pressure

Pressure is force spread over an area, measured in pascals (Pa), where one pascal is one newton per square metre. Practical units are much larger: a kilopascal, a bar (exactly 100,000 Pa) and the standard atmosphere (101,325 Pa). Tyre pressure is usually quoted in psi or bar, while weather reports use hectopascals, which are numerically identical to millibars. Gauge pressure and absolute pressure differ by atmospheric pressure.

Common pressure conversions

One bar expressed in other units of pressure
Unit	1 bar equals
Millibar (mbar)	1,000
Millimeter of mercury (mmHg)	750.06158
Kilopascal (kPa)	100
Inch of mercury (inHg)	29.529983
Pound per square inch (psi)	14.503774
Standard atmosphere (atm)	0.98692327
Megapascal (MPa)	0.1

Common bar and psi values

Common gauge pressures converted between bar and psi
Input	Result
1.5 bar	21.76 psi
2.2 bar	31.91 psi
3.5 bar	50.76 psi
7 bar	101.53 psi
45 psi	3.10 bar
200 psi	13.79 bar

Everyday uses

Tyre, bicycle and suspension pressure
Weather forecasts and altitude
Scuba diving and decompression planning
Hydraulics, pneumatics and gas work
HVAC and refrigeration systems

Frequently asked questions

What is standard atmospheric pressure?

101,325 Pa, which is 1.01325 bar, 14.696 psi or 760 mmHg. It is the average pressure at sea level.

How many psi are in one bar?

About 14.5038 psi, so a 2.2 bar tyre is roughly 32 psi.

Is a hectopascal the same as a millibar?

Numerically yes — both equal 100 Pa — but hectopascals are the SI-preferred wording in weather reports.

What is the difference between gauge and absolute pressure?

Gauge pressure ignores the atmosphere and reads zero at ambient conditions; absolute pressure includes it and reads about 1 bar at sea level.

More worked examples

One bar is exactly 100,000 pascals, which is about 14.5038 psi.
Standard atmospheric pressure at sea level is 101,325 Pa, or 1.01325 bar, or 14.696 psi.
A car tyre at 32 psi is about 2.206 bar.
One atmosphere is also 760 millimetres of mercury, or 101.325 kilopascals.

Quick reference

Common pressure units expressed in pascals
Unit	In pascals
1 pascal	1 N/m²
1 bar	100,000 Pa
1 atmosphere	101,325 Pa
1 psi	6,894.76 Pa
1 mmHg (torr)	133.322 Pa
1 inch of mercury	3,386.39 Pa
1 kg/cm²	98,066.5 Pa

Common mistakes to avoid

Treating gauge pressure and absolute pressure as the same thing. Tyre and boiler readings are usually gauge, meaning relative to the surrounding air.
Assuming bar and atmosphere are equal. One atmosphere is 1.01325 bar, which is about 1.3 percent higher.
Forgetting that psi means pounds-force per square inch, using force rather than mass.
Mixing kg/cm² with bar. One kg/cm² is 0.980665 bar, so the two are close but not identical.

Further questions

What is the difference between bar and psi?

One bar is 100,000 pascals and one psi is 6,894.76 pascals, so one bar is about 14.5 psi.

What is gauge pressure?

Pressure measured relative to the surrounding atmosphere. Absolute pressure equals gauge pressure plus atmospheric pressure.

Why is tyre pressure usually in psi in the United States?

Convention. Europe commonly uses bar or kilopascals for the same measurement.

Sources and standards

The pascal is one newton per square metre. NIST SP 811 gives the exact customary factors, including 1 psi = 6,894.757 Pa, and the bar is exactly 100,000 Pa rather than an approximation of atmospheric pressure.