Air Pressure Converter
Convert air and gas pressure between PSI, bar, kPa, MPa, atm, mmHg, and inHg.
Covers tire inflation, barometric pressure, HVAC, and scuba tank calculations.
Type in any field — the others update instantly.
Air pressure is measured in many units depending on the application.
Base unit: Pascal (Pa)
- 1 kPa = 1,000 Pa
- 1 bar = 100,000 Pa = 100 kPa
- 1 atm = 101,325 Pa = 101.325 kPa
- 1 PSI = 6,894.76 Pa = 6.89476 kPa
- 1 mmHg (torr) = 133.322 Pa
- 1 inHg = 3,386.39 Pa
Common conversions:
- 1 atm = 14.696 PSI = 1.01325 bar = 760 mmHg = 29.921 inHg
- 1 bar = 14.504 PSI = 100 kPa
- 1 PSI = 0.06895 bar = 6.895 kPa
Practical applications:
| Application | Typical Range | Common Unit |
|---|---|---|
| Car tires | 30–35 PSI / 2.1–2.4 bar | PSI or bar |
| Bicycle tires | 60–130 PSI / 4–9 bar | PSI or bar |
| Weather reports | 28.5–31 inHg / 965–1050 hPa | inHg or hPa |
| Blood pressure | 80–180 mmHg | mmHg |
| HVAC ducts | 0.05–1 inWG | inches of water |
Tire pressure is where this converter earns its keep, and it comes with a catch: the number on your door jamb is cold pressure, measured before driving. Tires heat up as you drive and the pressure climbs several PSI, so checking a hot tire reads high and tempts you to let air out, leaving you underinflated once it cools. Check first thing in the morning. Pressure also drops as the air cools, roughly 1 PSI for every 10°F (5.5°C), which is why tire warning lights pop up on the first cold morning of autumn even though nothing leaked.
The weather side uses the same physics from the other direction. Barometric pressure is reported in inHg in the US and hectopascals (millibars) elsewhere, and a falling reading signals an approaching storm while a rising one means clearing skies. Divers meet pressure most dramatically of all: every 10 meters (33 feet) of seawater adds one full atmosphere, so at 30 meters down a diver sits under four atmospheres, the reason scuba tanks and decompression tables exist. Same unit, wildly different stakes depending on where you meet it.
How we build and check this converter
This converter runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.