Free online pressure converter. Select any unit pair below or use the interactive converter.
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Pressure is the force applied per unit area on a surface. In physics and engineering, it is one of the most fundamental measurements used across industries — from checking your car tyre to monitoring blood pressure to designing aircraft engines. The standard SI unit of pressure is the Pascal (Pa), but different industries and countries use different units, making conversion essential.
Quick reference table — all values relative to 1 Pascal:
| Unit | Symbol | Equivalent to 1 Pa | Common Use |
|---|---|---|---|
| Pascal | Pa | 1 Pa | Science, SI standard |
| Kilopascal | kPa | 0.001 kPa | Weather, medical |
| Megapascal | MPa | 0.000001 MPa | Engineering, hydraulics |
| Bar | bar | 0.00001 bar | Meteorology, diving |
| Millibar | mbar | 0.01 mbar | Weather forecasting |
| PSI | psi | 0.000145 psi | US tyres, gas cylinders |
| Atmosphere | atm | 0.00000987 atm | Aviation, chemistry |
| Torr | Torr | 0.00750 Torr | Vacuum systems, labs |
| Situation | Pressure (approx) |
|---|---|
| Normal atmospheric pressure at sea level | 101,325 Pa / 1 atm / 14.7 psi |
| Car tyre pressure | 30–35 psi / 2.0–2.4 bar |
| Blood pressure (systolic, normal) | 120 mmHg / 16 kPa |
| Scuba diving at 10m depth | 2 atm / 202,650 Pa |
| Bicycle tyre pressure | 80–130 psi / 5.5–9 bar |
| LPG gas cylinder | 800–1000 kPa / 8–10 bar |
| Aircraft cabin pressure | 75 kPa / 0.75 atm |
The SI unit of pressure is the Pascal (Pa). It is defined as one Newton of force per square meter (N/m²). All other pressure units can be converted to and from Pascal.
Multiply the bar value by 14.5038. For example: 2 bar = 2 × 14.5038 = 29.0 psi. Use the converter above for instant results.
1 atmosphere (atm) = 101,325 Pascal (Pa). This is the standard atmospheric pressure at sea level.
Both bar and PSI measure pressure, but they come from different systems. Bar is metric (1 bar = 100,000 Pa), while PSI (pounds per square inch) is imperial. 1 bar ≈ 14.5 psi.
4 kPa = 4,000 Pa = 0.04 bar. Formula: divide kPa by 100 to get bar.
Tyre pressure is measured in PSI (pounds per square inch) in the US and bar or kPa in most other countries. A standard car tyre is typically inflated to 30–35 psi (2.0–2.4 bar).
Absolute pressure is measured relative to a perfect vacuum (zero pressure). Gauge pressure is measured relative to atmospheric pressure. For example, a car tyre showing 32 psi on a gauge actually has an absolute pressure of 32 + 14.7 = 46.7 psi.