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Tire Pressure Converter

Converter

Conversion Mode

32 psi equals

2.21

bar

Bar

32 psi × 0.0689476 = 2.21 bar

Typical Tire Pressure Ranges

Vehicle TypePSIBarkPa
Passenger Car28–361.93–2.48193–248
Motorcycle28–421.93–2.90193–290
Bicycle30–1302.07–8.96207–896
Light Truck / SUV32–802.21–5.52221–552
RV / Motorhome55–1103.79–7.58379–758

Quick Conversion Reference (PSI to other units)

PSIBarkPakgf/cm²
251.72172.41.758
281.93193.11.969
302.07206.82.109
322.21220.62.250
352.41241.32.461
362.48248.22.531
402.76275.82.812
443.03303.43.094
503.45344.73.515
604.14413.74.218
805.52551.65.625
1006.89689.57.031

About This Tool

Tire Pressure Converter – PSI, Bar, kPa, kgf/cm², atm & mmHg

Tire pressure is one of the most important—and most neglected—factors in vehicle safety and fuel economy. Yet pressure specifications appear in different units depending on where you are in the world or what kind of gauge you own: PSI in North America, Bar across Europe and much of Asia, kPa (kilopascal) in Australia and modern automotive manuals, and kgf/cm² on older Asian gauges. This tool converts tire pressure between all of these units—and adds vehicle presets, axle comparison, and temperature compensation—so you always have the right number for your gauge.

Understanding the Common Tire Pressure Units

PSI (pounds per square inch) is the dominant unit in the United States and Canada. Most passenger cars are inflated to 30–36 PSI cold. The number printed on a tire sidewall (often 44–51 PSI) is the maximum allowable pressure, not the recommended operating pressure.

Bar is a metric unit equal to exactly 100 kPa. One bar is very close to one standard atmosphere (1 atm = 1.01325 bar). European tire gauges almost always read in bar. A typical car tire at 32 PSI equals approximately 2.21 bar.

kPa (kilopascal) is the SI unit of pressure. Automotive standards bodies in Australia, Canada, and Japan specify pressures in kPa in owners' manuals. The same 32 PSI tire reads 220.6 kPa.

kgf/cm² (kilogram-force per square centimetre) is a legacy technical unit still found on older gauges in some Asian countries. 32 PSI ≈ 2.25 kgf/cm². It is very close to bar (1 bar = 1.01972 kgf/cm²).

Conversion Formulas

All conversions in this tool route through kPa as the intermediate unit to minimise floating-point error. The exact factors are:

  • 1 PSI = 6.894757 kPa
  • 1 bar = 100 kPa (exactly)
  • 1 kgf/cm² = 98.0665 kPa
  • 1 atm = 101.325 kPa
  • 1 mmHg = 0.133322 kPa

For example, to convert 220 kPa to PSI: 220 ÷ 6.894757 ≈ 31.9 PSI.

Front/Rear Axle Comparison

Many vehicles—particularly trucks, SUVs, motorcycles, and sports cars—call for different pressures on the front and rear axles. The axle comparison mode lets you enter both values at once, convert them to any target unit, and see the difference side by side. Entering the front and rear pressures in PSI and converting to bar, for example, makes it easy to set both tyres correctly when using a European gauge.

Temperature Compensation

Tire pressure rises and falls with temperature because the trapped air behaves like an ideal gas at constant volume. The relationship is described by Gay-Lussac's Law: P₂ = P₁_abs × (T₂ / T₁), where temperatures are in Kelvin and pressures are in absolute form (gauge + 1 atm). As a practical rule of thumb, pressure changes roughly 1 PSI per 10°F (about 0.07 bar per 5.5°C).

This matters because manufacturers specify cold tire pressure—measured after the vehicle has been stationary for at least three hours or driven less than 1.6 km. Checking pressure when tires are hot can give a reading 28–41 kPa (4–6 PSI) higher than the cold value. Use the temperature compensation mode to estimate how a specified cold pressure will read at a different ambient temperature, or to back-calculate the cold pressure from a hot reading.

Vehicle Presets and Typical Ranges

The tool includes one-click presets for passenger cars, motorcycles, bicycles, light trucks, and RVs/motorhomes. Each preset fills in the typical recommended pressure for that vehicle type. Always verify against your specific vehicle's placard—found on the driver's door jamb or in the owner's manual—since exact values vary by make, model, load, and tire size. The tire sidewall figure is the maximum inflation limit, not the recommended operating pressure.

Practical Tips for Accurate Tire Pressure Readings

  • Check pressure first thing in the morning after the vehicle has been parked overnight for the most accurate cold reading.
  • Keep a quality digital gauge in the car—cheap dial gauges can be off by 3–5 PSI.
  • Inflate to the placard value, not to the maximum printed on the sidewall. Overinflating reduces the contact patch, causes premature center-tread wear, and can make the ride dangerously stiff.
  • Underinflation is the more common and dangerous error. Soft tires flex more, generate heat, and are the leading cause of tire blowouts. They also increase rolling resistance and reduce fuel economy by up to 3%.
  • Check pressure at least monthly and before any long trip.

Global Unit Differences at a Glance

If you are crossing a border with your vehicle or comparing tire specs from an international source, the quick conversion reference table shows common PSI values in bar, kPa, and kgf/cm² side by side. For a full multi-unit breakdown, select the All Units mode to see your chosen pressure expressed simultaneously in all six supported units.

Frequently Asked Questions

Is the Tire Pressure Converter free?

Yes, Tire Pressure Converter is totally free :)

Can I use the Tire Pressure Converter offline?

Yes, you can install the webapp as PWA.

Is it safe to use Tire Pressure Converter?

Yes, any data related to Tire Pressure Converter only stored in your browser (if storage required). You can simply clear browser cache to clear all the stored data. We do not store any data on server.

How does the Tire Pressure Converter work?

Enter a tire pressure value and choose the source unit (PSI, Bar, kPa, kgf/cm², atm, or mmHg). The tool instantly converts the value to your chosen target unit — or to all units at once using the comparison table. All conversions route through kPa as an intermediate step to minimise floating-point error.

What is the difference between PSI, Bar, and kPa for tire pressure?

PSI (pounds per square inch) is the standard in the United States. Bar is common in Europe, Asia, and Africa — 1 bar ≈ 14.5 PSI. kPa (kilopascal) is the SI unit preferred in Australia, Canada, and many automotive manuals. A typical car tire of 32 PSI equals approximately 2.21 bar or 220.6 kPa.

Why should tire pressure be checked when the tires are cold?

Driving heats the air inside tires, which expands and raises the pressure. Checking hot tires can give a reading 4–6 PSI higher than the cold value your car manufacturer specifies. For accurate results, check pressure after the vehicle has been parked for at least three hours or driven less than 1 mile (1.6 km).

How accurate are the tire pressure conversions?

Conversions use internationally accepted factors (1 PSI = 6.894757 kPa exactly; 1 bar = 100 kPa exactly; 1 kgf/cm² = 98.0665 kPa; 1 atm = 101.325 kPa; 1 mmHg = 0.133322 kPa). Results are accurate to the number of decimal places you select (0–6). For gauge readings from a tire pressure gauge, the limiting factor is the gauge itself, typically ±0.5–1 PSI.

What is the temperature compensation feature?

The temperature compensation calculator applies Gay-Lussac's Law: P₂ = P₁_abs × (T₂ / T₁), where temperatures are in Kelvin and pressures are converted to absolute (gauge + 1 atm) before applying the ratio. This estimates how tire pressure changes with ambient temperature — useful for understanding why tires read lower on cold mornings. As a rule of thumb, pressure changes roughly 1 PSI per 10°F (0.07 bar per 5.5°C).

What are typical tire pressures for different vehicle types?

Passenger cars: 28–36 PSI (193–248 kPa). Motorcycles: 28–42 PSI depending on front/rear position. Bicycles: 30–130 PSI depending on tire width (road tires need more pressure than mountain bike tires). Light trucks and SUVs: 35–45 PSI unloaded, up to 80 PSI when loaded. Always follow the manufacturer's placard on the driver's door jamb rather than the maximum figure printed on the tire sidewall.