Tire Pressure Unit Converter
Tire pressure is critical for vehicle safety, fuel efficiency, and tire longevity. North American vehicles use psi (pounds per square inch), European vehicles often use bar, and many countries (as well as TPMS displays) use kilopascals (kPa). All three units are gauge pressure: the pressure above atmospheric. This converter instantly converts between psi, bar, and kPa using the exact NIST conversion: 1 psi = 6,894.757 Pa exactly.
Tire pressure conversion factors
1 psi = 0.0689476 bar = 6.89476 kPa
These are gauge pressures. The exact factor is 1 psi = 6,894.757 Pa = 6.894757 kPa. One bar = 100 kPa = 14.5038 psi.
Common tire pressure values
- Compact cars: 28 to 36 psi (1.93 to 2.48 bar, 193 to 248 kPa).
- SUVs and trucks: 35 to 45 psi (2.41 to 3.10 bar, 241 to 310 kPa).
- Road bicycles: 80 to 130 psi (5.52 to 8.96 bar, 552 to 896 kPa).
- Mountain bikes: 20 to 35 psi (1.38 to 2.41 bar, 138 to 241 kPa).
- Semi truck (steer tires): 105 to 120 psi (7.24 to 8.27 bar, 724 to 827 kPa).
Tire pressure converter: frequently asked questions
How do I convert psi to bar for tire pressure?
Divide psi by 14.5038 to get bar. For example, 32 psi (a common passenger car tire pressure) equals 32 / 14.5038 = 2.21 bar. Alternatively, multiply psi by 0.0689476.
What is the typical tire pressure for passenger cars?
Most passenger cars require 30 to 35 psi (2.07 to 2.41 bar, or 207 to 241 kPa). The correct pressure for your vehicle is listed on the door jamb placard on the driver's side, not on the tire sidewall (which shows maximum pressure).
What is the difference between gauge pressure and absolute pressure?
Tire pressure gauges measure gauge pressure: pressure relative to atmospheric pressure (approximately 14.7 psi or 1.013 bar). Absolute pressure = gauge pressure + atmospheric pressure. Tire specs always use gauge pressure (psig), not absolute (psia).
Why does cold tire pressure matter?
Tire pressure changes by approximately 1 psi for every 10 degrees Fahrenheit (5.6 C) change in temperature. Manufacturers specify cold inflation pressure, measured after the vehicle has been parked for at least 3 hours. Hot tires can read 4 to 6 psi higher than cold.
What psi should I set for a bicycle tire?
Road bike tires typically use 80 to 130 psi (5.5 to 9.0 bar). Mountain bike tires run 20 to 35 psi (1.4 to 2.4 bar). The correct pressure depends on tire width, rider weight, and terrain. Always check the tire sidewall for the rated range.
Official sources
- NIST Special Publication 811: Guide for the Use of the International System of Units (SI).
- NHTSA Tire Safety: Tire Safety and Inflation Guidance.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.