How to convert psi to bar
psi is pounds-force per square inch. One bar is 100,000 pascals, or 100 kPa. The pound and the inch are defined exactly in metric units, so 1 psi is 6.894757 kPa and 1 bar is 14.503774 psi.
bar = psi ÷ 14.503774
psi = bar × 14.503774
kPa = psi × 6.894757
kg/cm² = kPa ÷ 98.0665
atm = kPa ÷ 101.325kg/cm² here means kilogram-force per square centimeter: a force of 9.80665 N on 1 cm². Standard gravity is defined as exactly 9.80665 m/s², so 1 kg/cm² is exactly 98.0665 kPa, a little under 1 bar. The standard atmosphere is defined as exactly 101.325 kPa, which is 14.696 psi.
Worked examples
- 35 psi ÷ 14.503774 = 2.413 bar, which is 241.3 kPa or 2.461 kg/cm².
- 2.5 bar × 14.503774 = 36.26 psi.
- 32 psi × 6.894757 = 220.6 kPa.
Gauge pressure and absolute pressure
A tire gauge reads gauge pressure: how far the pressure inside the tire is above the air around it. A flat tire reads zero, even though the air inside is still at about 1 atm. Absolute pressure is measured from a vacuum, which is how the atm unit and most scientific figures work. At the standard atmosphere, a tire reading 32 psi on the gauge holds about 46.7 psi absolute.
This converter changes units only. A gauge figure stays a gauge figure and an absolute figure stays absolute. Some documents make it clear with psig and psia, or bar(g) and bar(a).
Where you meet these units
- Tire pressure: US placards and gauges use psi; much of the world uses bar or kPa, and some older gauges show kg/cm². Truck and trailer tires run far higher pressures than cars, which is why the table goes to 120 psi. This page does not recommend a pressure for any vehicle: use the placard and the owner's manual.
- Turbo boost: boost gauges read psi or bar above the atmosphere. The boost calculator works with both.
- Compressors and air tools: ratings are usually printed in psi and bar.
Questions
How many bar is 35 psi?
35 psi is 2.413 bar. Divide psi by 14.503774 to get bar.
How many psi is 2.5 bar?
2.5 bar is 36.26 psi. Multiply bar by 14.503774. For example, 2.2 bar is 31.91 psi and 3.0 bar is 43.51 psi.
Is kg/cm2 the same as bar?
Close, but not the same. 1 kg/cm² is 0.980665 bar, or 14.22 psi. So 2.5 bar is 2.549 kg/cm².
How many kPa is 32 psi?
32 psi is 220.6 kPa, or 2.206 bar. Multiply psi by 6.894757 to get kPa.