1
The driver's door pillar
Open the driver's door and look at the door shut or the pillar it closes against. Most cars carry a placard there listing front and rear pressures, often for more than one tyre size and load.
Free tyre pressure tool
PSI to bar tyre pressure converter
Divide PSI by 14.5 to get bar, or multiply bar by 14.5 to get PSI. Convert any pressure between PSI, bar and kPa below, then check it against your car's placard.
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PSI, bar and kPa
How do you convert tyre pressure from PSI to bar?
Divide PSI by 14.5 to get bar, or multiply bar by 14.5 to get PSI. One bar is exactly 100 kPa and one PSI is about 6.9 kPa. So 32 PSI is 2.21 bar (221 kPa), and 2.4 bar is 34.8 PSI.
The conversions at a glance
- 1 bar = 14.5 PSI = 100 kPa
- 1 PSI = 0.069 bar = 6.9 kPa
- PSI to bar: divide by 14.5. Bar to PSI: multiply by 14.5
- kPa to bar: divide by 100. Bar to kPa: multiply by 100
The converter uses the exact factor of 1 PSI = 6.894757 kPa. The tables below cover every common setting, so you can convert without the tool.
Quick reference
Tyre pressure conversion table
Every whole PSI from 26 to 50, and bar figures as they appear on many placards. Bar is rounded to two decimal places, PSI to one and kPa to the nearest whole number.
| PSI | bar | kPa |
|---|---|---|
| 26 | 1.79 | 179 |
| 27 | 1.86 | 186 |
| 28 | 1.93 | 193 |
| 29 | 2.00 | 200 |
| 30 | 2.07 | 207 |
| 31 | 2.14 | 214 |
| 32 | 2.21 | 221 |
| 33 | 2.28 | 228 |
| 34 | 2.34 | 234 |
| 35 | 2.41 | 241 |
| 36 | 2.48 | 248 |
| 37 | 2.55 | 255 |
| 38 | 2.62 | 262 |
| 39 | 2.69 | 269 |
| 40 | 2.76 | 276 |
| 41 | 2.83 | 283 |
| 42 | 2.90 | 290 |
| 43 | 2.96 | 296 |
| 44 | 3.03 | 303 |
| 45 | 3.10 | 310 |
| 46 | 3.17 | 317 |
| 47 | 3.24 | 324 |
| 48 | 3.31 | 331 |
| 49 | 3.38 | 338 |
| 50 | 3.45 | 345 |
| 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 |
Your car's figure
Where do you find your car's correct tyre pressure?
The right pressure is set by the car manufacturer for your model and tyre size, not by the tyre maker. TyreSafe points drivers to three places.
2
Inside the fuel flap
Many cars print the same table inside the fuel filler flap, which is handy because you can read it standing at the air line.
3
The handbook
The handbook has the full table, including each wheel size the car was sold with and the figures for a full load. If the placard is missing or unreadable, this is the one to trust.
The number moulded into the tyre sidewall is the maximum pressure that tyre can hold, not the pressure your car should run, so do not inflate to it. Placards often give different front and rear figures, and many list a normal and a laden pressure. Pick the row that matches the tyre size actually fitted and how loaded the car is.
Placards and gauges do not always use the same unit: one may show bar or kPa while the other reads in PSI. That mismatch is exactly what the converter above is for. Our correct tyre pressure guide walks through each line of a typical placard.
Cold or hot
Should you check tyre pressure when the tyres are cold?
Yes. The Highway Code says to check before your journey, when tyres are cold, because warm or hot tyres may give a misleading reading. Driving warms the air inside the tyre and the pressure rises above the cold figure the placard is written for.
- Check cold. Before you set off, or after only a short, gentle drive to the nearest air line.
- Do not let air out of warm tyres to match the cold figure. Once they cool down they will be under-inflated.
- Use an accurate gauge. TyreSafe advises checking at least every month and before long journeys, and the Highway Code suggests a weekly check.
- Include the spare, if your car carries one, so it is ready when you need it.
- Refit the valve caps. They keep dirt and moisture out of the valve.
Cold weather lowers tyre pressure too, so a tyre that was right in summer can read low on a frosty morning. Our guides on tyre pressure in cold weather and how often to check your tyre pressure cover both.
Loads and towing
When should you use a higher tyre pressure?
When the car is carrying more weight. The Highway Code says tyres must be inflated to the vehicle manufacturer's specification for the load being carried.
In practice that means reading the laden column on the placard or in the handbook whenever the car is full of passengers and luggage, then going back to the normal figure once the load is off. It is worth checking before any long, fully loaded drive.
Towing works the same way. TyreSafe notes that your pressures may need to change when you pull a caravan or trailer, and the car's handbook gives the figure to use. The caravan or trailer has its own tyres and its own pressures from its manufacturer, which our caravan and trailer tyre guide covers.
If the car has a different tyre size from standard, or extra-load (XL) tyres, use the figure for the tyres actually fitted. A converter changes the units, not the recommendation, so the number you convert should always come from your car's own documentation. Our guide to load index and speed ratings explains the XL marking.
Why it matters
What does under-inflation do to a tyre?
A tyre that is a few PSI low does not look flat, which is why it goes unnoticed. TyreSafe sets out what running on it does.
Faster, uneven wear
An under-inflated tyre flexes too much and wears quickly on the tread shoulders, the outer edges, so it needs replacing sooner than a tyre kept at the right pressure.
Poorer handling and grip
TyreSafe warns that low pressure affects handling and grip and can make a car behave unpredictably. It links correct pressures with better control and less chance of aquaplaning.
More fuel, more damage
A soft tyre takes more effort to roll, which raises fuel consumption. The extra flexing also wears the casing, and the tyre and wheel are more easily damaged by potholes and kerbs.
If one tyre keeps dropping after you top it up, the cause is usually a slow puncture, a leaking valve or a wheel that no longer seals against the tyre. That needs a proper look rather than more air. See our slow puncture guide, or book a mobile puncture repair and we come to the car. If a warning light has come on, our guide to the tyre pressure warning light explains what it means.
FAQs
Tyre pressure units, answered.
Sources: the Highway Code, Annex 6 on checking pressures cold and inflating for the load; TyreSafe on car tyre pressures and under-inflation and towing; NIST for the PSI to kPa conversion factor.
How many PSI is 2.2 bar?
2.2 bar is 31.9 PSI, which is 220 kPa. On an air line that only shows whole numbers, 32 PSI is the nearest setting.
What is 35 PSI in bar?
35 PSI is 2.41 bar, or 241 kPa. To turn any PSI figure into bar, divide it by 14.5.
How do I convert bar to PSI?
Multiply the bar figure by 14.5. For example, 2.3 bar is 33.4 PSI and 2.5 bar is 36.3 PSI. One bar is also exactly 100 kPa.
Should I use the pressure written on the tyre sidewall?
No. The figure on the sidewall is the maximum pressure the tyre can take, not the pressure for your car. Use the figure on the driver's door pillar, inside the fuel flap or in the handbook.
Should I check tyre pressure hot or cold?
Cold. The Highway Code advises checking before a journey, when tyres are cold, because warm tyres can give a misleading reading. Do not let air out of a warm tyre to match the cold figure.
Do I need more air when towing or carrying a full load?
Often, yes. The Highway Code says tyres must be inflated to the manufacturer's specification for the load being carried, and TyreSafe notes that pressures may need to change when towing. Use the laden or towing figure from your handbook.
Tyre keeps going down?
Losing pressure?
Losing pressure?
We come to you.
A tyre that will not hold its pressure needs a proper look. Call, WhatsApp or book online. The price is agreed on the call before any work starts.