Quick answer: Pressure is force per unit area, measured in pascals in the SI system. Key references: one standard atmosphere is 101.325 kilopascals, 14.696 psi, or 760 millimeters of mercury. This converter covers pascals, bar, psi, atmospheres and mmHg for tires, weather reports in hectopascals, and diving gauges.
Last reviewed: September 2026
Key facts
- 1 atm = 101.325 kPa = 14.696 psi — the pressure of the atmosphere at sea level.
- 1 bar = 100 kPa = 14.504 psi; 30 psi = 2.07 bar.
- A typical car tyre is ~32 psi (≈ 2.2 bar); bike tyres run 60–120 psi.
- Blood pressure 120/80 is measured in mmHg — millimetres of mercury.
Tyre gauges read psi, European cars quote bar, weather maps use hectopascals — pressure units are everywhere and never agree. This free pressure converter translates between pascals, kilopascals, bar, psi, atmospheres and mmHg instantly.
Enter a value and choose your units. It is perfect for checking tyre pressures abroad, reading dive tables and making sense of weather reports.
How to use
- Enter a value.
- Choose the from and to units.
- Read the answer and the full table of equivalents below.
How pressure conversion works
| Term | Meaning |
|---|---|
| from-unit in kPa | Each unit’s exact definition in kilopascals. |
| to-unit in kPa | The target unit’s definition in kilopascals. |
Pressure is force per area — which is why the SI unit, the pascal, is one newton per square metre.
Worked examples
Tyre pressure
30 psi → bar: 30 × 0.0689476 = 2.07 bar.
2 bar → psi: 2 × 14.5038 = 29.01 psi — so a European “2.2 bar” recommendation is about 32 psi.
Atmosphere and weather
1 atm → kPa: 101.325 kPa exactly.
1,013 hPa weather report → kPa: 1 hPa = 0.1 kPa, so 1,013 hPa = 101.3 kPa ≈ 1 atm — standard sea-level pressure.
Pressure units in kilopascals
| Unit | Equals (kPa) | You meet it in |
|---|---|---|
| Pascal (Pa) | 0.001 | Physics, SI base |
| Kilopascal (kPa) | 1 | Engineering, weather (as hPa) |
| Bar | 100 | European tyres, diving |
| psi | 6.89476 | US/UK tyres, tools |
| Atmosphere (atm) | 101.325 | Sea-level air pressure |
| mmHg | 0.133322 | Blood pressure, medicine |
Frequently asked questions
How do I convert psi to bar?
Multiply psi by 0.0689476 (or divide by 14.504): 32 psi ≈ 2.21 bar.
What is the difference between bar and atm?
1 atm = 101.325 kPa; 1 bar = 100 kPa. They differ by about 1.3% — close enough for tyres, not for lab work.
What tyre pressure should I use?
Check the sticker inside the driver’s door or the manual — typically 30–35 psi (2.1–2.4 bar) for cars. Never exceed the tyre’s printed maximum.
Why is blood pressure in mmHg?
Mercury manometers were the original instruments; 120/80 mmHg stuck as the unit even after mercury was phased out.
What is a hectopascal in weather reports?
1 hPa = 100 Pa = 0.1 kPa. Standard sea-level pressure is 1,013.25 hPa; lower means stormier weather.
Sources
Key takeaways
- 1 atm = 101.325 kPa = 14.696 psi; 1 bar = 100 kPa = 14.504 psi.
- Car tyres: ~32 psi ≈ 2.2 bar — check your door sticker, not the tyre wall.
- Weather hPa are tenths of kPa: 1,013 hPa ≈ 1 atmosphere.
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