Pressure Converter
Convert between Pascal, Kilopascal, Bar, Atmosphere, PSI, mmHg, and inHg instantly.
Quick Reference
How to Convert Pressure Units
Pressure is defined as force per unit area. This converter works by converting every input to the base unit (Pascal), then to the target unit. Pressure measurement is critical in weather forecasting, tyre maintenance, medical readings, and engineering.
Common Conversion Factors
| From | To | Multiply by |
|---|---|---|
| Atmosphere | Pascal | 101,325 |
| Bar | Pascal | 100,000 |
| PSI | Pascal | 6,894.757 |
| mmHg | Pascal | 133.322 |
| inHg | Pascal | 3,386.39 |
| Kilopascal | Pascal | 1,000 |
| PSI | Bar | 0.0689476 |
Pressure in Everyday Life
Tire pressure is typically measured in PSI (32×35 PSI for cars) or bar (2.2×2.4 bar). Blood pressure is measured in mmHg — a normal reading is around 120/80 mmHg. Weather reports use millibars (hPa) or inHg; standard sea-level pressure is 1013.25 hPa or 29.92 inHg.
Pressure Quick Reference
| atm | kPa | PSI | bar | mmHg |
|---|---|---|---|---|
| 0.5 | 50.66 | 7.35 | 0.507 | 380 |
| 1 | 101.33 | 14.70 | 1.013 | 760 |
| 2 | 202.65 | 29.39 | 2.027 | 1520 |
| 5 | 506.63 | 73.48 | 5.066 | 3800 |
| 10 | 1013.25 | 146.96 | 10.133 | 7600 |
Why pressure has so many units
Pressure (force per unit area) shows up in atmospheric science, engineering, scuba diving, automotive maintenance, weather reporting, and medical instrumentation — each field having grown up with its own reference unit. The SI unit is the pascal (Pa = N/m²), but pascals are inconveniently small for most daily uses, so atmospheres, bars, psi, mmHg, and inHg all coexist. A confident understanding of one or two conversions handles 95% of real-world needs.
The conversions worth memorising
| Unit | Equals |
|---|---|
| 1 standard atmosphere (atm) | 101,325 Pa = 1.01325 bar = 14.696 psi |
| 1 bar | 100,000 Pa = 14.504 psi |
| 1 psi (pound per square inch) | 6,894.76 Pa |
| 1 mmHg (torr) | 133.322 Pa |
| 1 inHg (inches of mercury) | 3,386.39 Pa |
| 1 kPa | 1,000 Pa = 0.145 psi |
Where each unit dominates
- Weather reports: hectopascals (hPa) or millibars (1 hPa = 1 mbar). Standard sea-level pressure is 1013.25 hPa.
- Car tyres: psi in the US/UK, bar or kPa in Europe and Japan. Most cars want 30–35 psi (2.1–2.4 bar) cold.
- Blood pressure: mmHg. 120/80 mmHg is the canonical "normal".
- Scuba diving: bar (each 10 m of seawater adds 1 bar of gauge pressure).
- Aviation: inHg in the US (altimeter setting), hPa elsewhere. Sea-level standard is 29.92 inHg.
- Engineering and process industries: kPa or bar.
Gauge vs absolute — the one that trips people up
Pressure readings come in two flavours. Absolute pressure is measured against a perfect vacuum. Gauge pressure is measured against the surrounding atmospheric pressure (so a tyre at "32 psi" means 32 psi above atmospheric — its absolute pressure is around 47 psi at sea level). Manufacturers sometimes label PSIA (absolute) and PSIG (gauge), but often do not. Always check which is meant: confusing the two when calculating pump capacity or gas tank contents produces 14.7 psi (1 atm) of error.