Pressure Converter
Convert between pascals, bar, psi, atmospheres, and more pressure units.
Quick Reference — 1 unit = ? Kilopascal (kPa)
| Unit | Value |
|---|---|
| Pascal (Pa) | 0.001 |
| Kilopascal (kPa) | 1 |
| Megapascal (MPa) | 1000 |
| Bar | 100 |
| Millibar (mbar) | 0.1 |
| Atmosphere (atm) | 101.325 |
| PSI (lb/in²) | 6.89476 |
| Torr (mmHg) | 0.133322 |
Formula
Multiply by (from factor / to factor)
Everyday Uses
Tire pressure
The door sticker says 32 PSI, the garage pump reads bar (2.2) — convert so your tires are neither soft nor overinflated.
Weather maps
Barometric pressure in hPa, inHg, or mmHg depending on the source — convert to follow storms across different forecasts.
Diving and industry
Dive tables in bar, gauges in PSI, textbooks in atmospheres — convert between them where precision is safety.
Technical and medical readings
Pascals, kPa, mmHg — translate pressure readings between medical, engineering, and scientific contexts.
Frequently Asked Questions
How do you convert between psi, bar, and kPa?
1 bar = 100,000 Pa = 100 kPa = 14.504 psi. 1 psi = 6,894.76 Pa = 6.895 kPa = 0.0689 bar. 1 kPa = 1,000 Pa = 0.145 psi = 0.01 bar. Common tyre pressures: 32 psi = 2.21 bar = 220.6 kPa; 35 psi = 2.41 bar. Bicycle tyres: 80–130 psi (road) = 5.5–9 bar. To convert psi to bar: divide by 14.504. To convert bar to psi: multiply by 14.504.
What is standard atmospheric pressure in different units?
Standard atmosphere (1 atm) = 101,325 Pa = 101.325 kPa = 1.01325 bar = 14.696 psi = 760 mmHg (Torr) = 760 Torr. Sea-level air pressure supports a column of mercury 760 mm tall — this is why blood pressure and barometric readings use mmHg. Normal blood pressure is 120/80 mmHg. Weather barometers typically read 970–1,040 hPa (hectopascals = millibars); 1013 hPa is the standard sea-level average.
What is the difference between gauge pressure and absolute pressure?
Absolute pressure is measured relative to perfect vacuum (0 Pa). Gauge pressure is measured relative to current atmospheric pressure — this is what tyre gauges and blood pressure cuffs measure. Absolute = Gauge + Atmospheric. A tyre showing 35 psi gauge pressure has an absolute pressure of 35 + 14.7 = 49.7 psia. Negative gauge pressure indicates a vacuum below atmospheric: −14.7 psi gauge = perfect vacuum (0 psia). Industrial systems use "psig" (gauge) and "psia" (absolute) to distinguish them.
What are torr and mmHg, and where are they used?
1 Torr = 1 mmHg = 133.322 Pa. Torr and mmHg are historically based on the height of a mercury column in a barometer or manometer. Uses today: blood pressure (always reported in mmHg — e.g. 120/80 mmHg); vacuum systems in science and manufacturing (pressures below 1 Torr are considered vacuum; "high vacuum" is <10⁻³ Torr); ophthalmology (intraocular pressure, normal 10–21 mmHg); and gas laws in chemistry. Named after Evangelista Torricelli (1608–1647), who invented the mercury barometer.
How does pressure change with altitude and depth?
Altitude: atmospheric pressure drops roughly 1.2 kPa (0.17 psi) for every 100 m gained. At 1,000 m: ~89.9 kPa; at 5,500 m (Everest base camp): ~50 kPa; at 10,000 m (cruising altitude): ~26.5 kPa. Aircraft cabins are pressurised to ~75 kPa (equivalent to ~2,400 m altitude). Underwater: pressure increases by ~100 kPa (1 atm) for every 10 metres of depth. At 10 m depth: 2 atm; at 100 m: 11 atm. This is why scuba tanks must hold gas at high pressure (~200 bar).