Tyre Pressure: PSI, Bar and kPa Guide
Quick Answer
Common passenger car tyre pressures: 32 PSI = 2.21 bar = 220.6 kPa | 35 PSI = 2.41 bar = 241.3 kPa | 38 PSI = 2.62 bar = 262.0 kPa
- PSI to bar: bar = PSI × 0.0689
- Bar to PSI: PSI = bar × 14.504
- PSI to kPa: kPa = PSI × 6.895
- kPa to PSI: PSI = kPa ÷ 6.895
Find your correct tyre pressure on the sticker inside your driver's door or in your car handbook.
Tyre pressure is one of the most important aspects of vehicle maintenance. The right pressure improves safety, fuel economy and tyre life. Different countries and vehicles use different pressure units. This guide explains PSI, bar and kPa clearly. Use the free Pressure Converter on CalConvs for instant conversions.
The Three Pressure Units Used for Tyres
- PSI (pounds per square inch): Used in the United States, United Kingdom, Pakistan, India and most of Asia. The most common unit worldwide for consumer tyre gauges.
- Bar: Used in Europe and increasingly worldwide. 1 bar is approximately 14.5 PSI.
- kPa (kilopascal): The SI metric unit. Used in Australia, Canada and on many modern digital tyre gauges. 100 kPa = 1 bar.
Tyre Pressure Conversion Table
| PSI | Bar | kPa |
|---|---|---|
| 24 PSI | 1.65 bar | 165.5 kPa |
| 26 PSI | 1.79 bar | 179.3 kPa |
| 28 PSI | 1.93 bar | 193.1 kPa |
| 30 PSI | 2.07 bar | 206.8 kPa |
| 32 PSI | 2.21 bar | 220.6 kPa |
| 34 PSI | 2.34 bar | 234.4 kPa |
| 35 PSI | 2.41 bar | 241.3 kPa |
| 36 PSI | 2.48 bar | 248.2 kPa |
| 38 PSI | 2.62 bar | 262.0 kPa |
| 40 PSI | 2.76 bar | 275.8 kPa |
| 44 PSI | 3.03 bar | 303.4 kPa |
What Pressure Does My Car Need?
The correct tyre pressure is set by the vehicle manufacturer. Never use the maximum pressure printed on the tyre sidewall as your target. That is the maximum the tyre can handle, not what your car needs.
| Vehicle Type | Typical Pressure |
|---|---|
| Small car | 30 to 33 PSI (2.1 to 2.3 bar) |
| Medium car | 33 to 36 PSI (2.3 to 2.5 bar) |
| SUV | 35 to 44 PSI (2.4 to 3.0 bar) depending on load |
| Van or commercial vehicle | 44 to 65 PSI (3.0 to 4.5 bar) depending on load |
| Spare tyre (temporary) | Usually 60 PSI (4.1 bar). Check the label. |
Effects of Wrong Tyre Pressure
- Underinflation (too low): Tyre overheats, wears faster at edges, increases fuel consumption, risk of blowout, poor handling.
- Overinflation (too high): Tyre wears faster in the centre, reduced grip especially on wet roads, harsher ride.
- Correct inflation: Even wear across tread, optimal fuel economy, best braking performance and handling.
Tyre Pressure by Country
- United States: PSI standard. TPMS (tyre pressure monitoring) required on all new cars since 2008.
- United Kingdom: PSI most common for consumer gauges. Bar also widely used.
- Australia: kPa standard on most Australian tyre gauges. Door sticker usually shows kPa.
- Europe: Bar standard. All petrol station digital gauges show bar. TPMS required on new EU vehicles since 2014.
- India and Pakistan: PSI standard at petrol stations. Checking pressure before long journeys is strongly recommended given road conditions.
Frequently Asked Questions
What tyre pressure should I use?
Use the pressure specified by your vehicle manufacturer on the door sticker or in your handbook. A small city car and a large SUV with the same tyres need very different pressures. Never guess.
Does tyre pressure change with temperature?
Yes. Tyre pressure drops approximately 1 PSI (0.07 bar) for every 10°F (5.5°C) drop in temperature. Check pressure in cold weather and after hot motorway driving when the tyre has cooled down.
What is 2.4 bar in PSI?
2.4 bar equals approximately 34.8 PSI. Calculation: 2.4 × 14.504 = 34.8 PSI.
How often should I check tyre pressure?
Check monthly and before any long journey. Tyres naturally lose about 1 PSI per month. Temperature changes also affect pressure significantly.
Related Tools
- Pressure Converter: PSI, bar, kPa, atm, pascal and more
- All Unit Converters: 74 converters on CalConvs