Tyre Pressure Calculator 2026 with bar, psi & kPa Converter
Pick tyre width, profile, rim and load for a starting cold pressure, then convert any reading: 2.4 bar is 34.8 psi or 240 kPa. The door placard rules.
Recommended Tyre Pressure
This is a starting point worked out from tyre size and load only. The pressure printed on your car's placard or in the handbook overrides it, and every figure assumes cold tyres.
Tyre Pressure Converter: bar, psi and kPa
Type a reading into any box and the other two follow. The maths is fixed: 1 bar = 14.5038 psi = 100 kPa, so a "240" on a European placard (kPa) is 2.4 bar or 34.8 psi.
2.4 bar = 34.8 psi = 240 kPa
Tyre Pressure Conversion Chart
Straight unit conversions, rounded to one decimal (psi) and two decimals (bar). They say nothing about what your car needs; that figure is on the placard in the door frame or fuel flap.
| bar | psi | kPa |
|---|---|---|
| 1.8 | 26.1 | 180 |
| 1.9 | 27.6 | 190 |
| 2.0 | 29.0 | 200 |
| 2.1 | 30.5 | 210 |
| 2.2 | 31.9 | 220 |
| 2.3 | 33.4 | 230 |
| 2.4 | 34.8 | 240 |
| 2.5 | 36.3 | 250 |
| 2.6 | 37.7 | 260 |
| 2.7 | 39.2 | 270 |
| 2.8 | 40.6 | 280 |
| 2.9 | 42.1 | 290 |
| 3.0 | 43.5 | 300 |
| 3.1 | 45.0 | 310 |
| 3.2 | 46.4 | 320 |
| 3.3 | 47.9 | 330 |
| 3.4 | 49.3 | 340 |
| 3.5 | 50.8 | 350 |
| psi | bar | kPa |
|---|---|---|
| 26 | 1.79 | 179 |
| 28 | 1.93 | 193 |
| 30 | 2.07 | 207 |
| 32 | 2.21 | 221 |
| 34 | 2.34 | 234 |
| 36 | 2.48 | 248 |
| 38 | 2.62 | 262 |
| 40 | 2.76 | 276 |
| 42 | 2.90 | 290 |
| 44 | 3.03 | 303 |
Typical Pressures by Body Style
Ballpark cold figures only; individual models differ, so check the placard.
| Vehicle Type | Front (PSI) | Rear (PSI) | Front (bar) | Rear (bar) |
|---|---|---|---|---|
| Small hatchback | 30 | 28 | 2.1 | 1.9 |
| Saloon / Sedan | 32 | 30 | 2.2 | 2.1 |
| Estate / Wagon | 33 | 35 | 2.3 | 2.4 |
| SUV / Crossover | 33 | 33 | 2.3 | 2.3 |
| Van / Light commercial | 36 | 42 | 2.5 | 2.9 |
Placards in Europe print pressure in kPa or bar, pumps in the UK and US often show psi, and a handbook may use all three. The converter above handles that part exactly: 1 bar is 14.5038 psi and 100 kPa, so 2.3 bar is 33.4 psi and 230 kPa. The calculator above it does something rougher. From the tyre’s width, profile, rim size and how heavily the car is loaded, it suggests a cold starting pressure in all three units, which is useful when you cannot find the placard but is never a substitute for it.
How the calculator works
The base figure starts at 30 psi for narrow tyres and rises in steps to 36 psi for the widest, adds 1-2 psi for low-profile sidewalls (55 series and below) and for rims of 17 inches or more, then adds 2 psi for a medium load, 4 psi for a full load and 6 psi when towing. Those steps are a simplification of how pressure tracks size and load, so treat the output as a sanity check. If your reading is far away from it, look up the placard before you change anything.
Using the converter
Type into any of the three boxes and the other two update as you go. Typical searches it answers:
- “What is 240 tyre pressure in psi?” 240 kPa = 2.4 bar = 34.8 psi.
- “32 psi in bar?” 32 / 14.5038 = 2.21 bar (221 kPa).
- “2.5 bar in psi?” 2.5 x 14.5038 = 36.3 psi.
Pressure gauges on forecourt air lines are not always accurate, so a cheap hand gauge of your own gives more consistent readings.
Why the right pressure matters
An under-inflated tyre flexes more, runs hotter, wears its shoulders and lengthens braking distances; an over-inflated one shrinks the contact patch, loses grip and wears the centre of the tread. Check pressure monthly and before a long trip, with the tyres cold. The tyre pressure guide covers TPMS warnings, seasonal changes and what the numbers do to fuel use.
Data sources
Unit conversions use the standard definitions (1 bar = 100 kPa; 1 psi = 6.89476 kPa). The starting-pressure steps are this site’s simplification of manufacturer practice, not a published standard; vehicle placards and owner’s manuals take precedence.
Frequently Asked Questions
The figure your car needs is printed on a placard inside the driver's door frame (sometimes the fuel flap or glovebox) and in the owner's manual. Typical passenger-car values fall around 30-35 psi (2.0-2.4 bar), but use the placard rather than a general range.
A pressure of 240 on a European placard is in kPa. Divide by 100 to get 2.4 bar, then multiply by 14.5038 to get 34.8 psi.
Multiply bar by 14.5038. So 2.0 bar is 29.0 psi, 2.3 bar is 33.4 psi and 2.5 bar is 36.3 psi. To go the other way, divide psi by 14.5038; for kPa, multiply bar by 100.
Yes. Many placards list a separate, higher figure for a fully loaded car, and that is the one to use. When the placard is not to hand, this calculator adds 2, 4 or 6 psi for a medium load, a full load and towing as a rough stand-in.
Yes. A common rule of thumb is about 1 psi (0.07 bar) lost for every 10°F (5.5°C) drop in air temperature, so readings fall in autumn. Always measure cold, before driving or after only a short distance.