Tire Pressure Conversion Calculator
Convert tire pressure between PSI (pounds per square inch), bar, and kPa (kilopascals). Enter any one value and the other two units are calculated instantly. Passenger car tires are typically inflated to 30 to 35 PSI (2.07 to 2.41 bar, 207 to 241 kPa). Always use the cold inflation pressure from your vehicle's door-jamb placard, not the maximum pressure printed on the tire sidewall.
Tire pressure conversion formulas
PSI to bar: bar = PSI x 0.0689476
PSI to kPa: kPa = PSI x 6.89476
bar to PSI: PSI = bar x 14.5038
kPa to PSI: PSI = kPa x 0.145038
bar to kPa: kPa = bar x 100
These factors are exact derived values from the SI definitions: 1 pound-force = 4.44822 N; 1 square inch = 6.4516 x 10^-4 m^2; 1 Pa = 1 N/m^2; 1 bar = 100,000 Pa (NIST SP 330, 2019 edition).
Recommended tire pressure by vehicle type
- Passenger car: 30 to 35 PSI (2.07 to 2.41 bar, 207 to 241 kPa). Always check the door placard for your specific vehicle.
- Light truck and SUV: 35 to 45 PSI (2.41 to 3.10 bar) depending on load rating.
- Full-size pickup (light load): typically 35 to 45 PSI front; 45 to 65 PSI rear when loaded to capacity.
- Temporary spare (compact spare): typically 60 PSI. Check the spare's sidewall and placard.
- Motorcycle: varies widely by tire size and load, typically 28 to 42 PSI. Always check the motorcycle's specific placard.
Tire pressure conversion calculator: frequently asked questions
What is the correct tire pressure for my car?
The correct tire pressure for your vehicle is printed on the door-jamb placard (driver's door or door post) and in the owner's manual. This placard specifies cold inflation pressure in PSI for front and rear tires at full load. The number on the tire sidewall is the maximum pressure the tire can handle, not the recommended operating pressure for your vehicle.
How do you convert PSI to bar?
1 PSI = 0.0689476 bar. So to convert PSI to bar: bar = PSI x 0.0689476. For quick mental math, 1 bar is approximately 14.50 PSI. Typical passenger car tire pressure of 32 to 35 PSI equals approximately 2.21 to 2.41 bar. This conversion follows the international standard: 1 bar = 100,000 Pascals (NIST SP 330).
How do you convert PSI to kPa?
1 PSI = 6.89476 kPa. So kPa = PSI x 6.89476. Many Canadian and European vehicle placards use kPa. Typical tire pressure of 35 PSI equals approximately 241 kPa. The kilopascal (kPa) is an SI unit: 1 kPa = 1,000 Pascals = 1,000 N/m^2.
What happens if my tire pressure is too low or too high?
Under-inflated tires: increased rolling resistance (worse fuel economy by up to 0.5% per PSI below recommended per the EPA), uneven wear on the outer edges, overheating, and increased risk of blowout. Over-inflated tires: reduced contact patch, harsher ride, uneven center wear, and reduced wet-weather traction. NHTSA estimates that 26% of passenger cars are driven with at least one significantly under-inflated tire.
Should I check tire pressure when tires are hot or cold?
Always check and set tire pressure when the tires are cold (driven less than 1 mile or parked for at least 3 hours). Tire pressure increases by approximately 1 PSI for every 10 degrees Fahrenheit of temperature increase, per the Tire Industry Association. The placard values are cold inflation pressures. If you must check hot tires, add 4 PSI to the placard value as a temporary guide, then recheck when cold.
Official sources
- NHTSA Tire Safety: nhtsa.gov/equipment/tires.
- NIST SP 330 (SI unit conversion factors): nist.gov SP 330 2019 edition.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.