How-to

How to Check Your Tyre Pressure

Correct tyre pressure keeps you safe on the road, saves you money at the pump, and helps your tyres last longer. Here's everything you need to know, including how to check it yourself in under five minutes.

7 min read·Updated May 2026

Key Takeaway

Check all four tyres once a month and before any long journey, always when the tyres are cold. Find your car's recommended PSI on the driver's door sill sticker. A tyre can be significantly underinflated without looking flat, so always use a gauge.

Why Tyre Pressure Matters

Your tyres are the only part of your car that actually touches the road. Getting the pressure right might sound like a minor detail, but it has a surprisingly big impact on several things at once:

Safety. Underinflated tyres handle poorly, take longer to stop, and are more likely to suffer a blowout at speed. Overinflated tyres have less grip and wear unevenly in the centre.
Fuel economy. Correctly inflated tyres roll more efficiently. Underinflated tyres increase rolling resistance, which means your engine works harder and burns more fuel. The AA estimates that tyres inflated just 8 PSI below the recommended level can increase fuel consumption by around 4%.
Tyre life. Incorrect pressure causes uneven wear, meaning you'll need to replace tyres sooner than you should.
Legal compliance. Excessively worn or visibly underinflated tyres can result in a fine and points on your licence.

It's one of the simplest things you can do to keep your car roadworthy. And if you're buying a used car, checking that its tyres have been properly maintained, alongside a full service history check from ServiceStamp, gives you a much clearer picture of how the car has been looked after.

What Tyre Pressure Should My Car Be?

There's no single universal answer. The correct pressure varies by car, tyre size, and sometimes by whether you're carrying a full load or just driving solo. You'll find the recommended pressures in one of three places:

The driver's door sill. Most cars have a sticker on the inside of the driver's door or door frame listing the recommended pressures for front and rear tyres.
The fuel filler cap. Some manufacturers print the information here.
Your owner's manual. Always the definitive reference if you're unsure.

Tyre pressure is measured in PSI (pounds per square inch) or BAR. Most passenger cars run somewhere between 28 and 36 PSI, but always check your car's specific recommendation rather than guessing.

Note: Many cars have different recommended pressures for the front and rear tyres, and some have a higher recommended pressure when carrying a full load or towing. Always check which applies to your situation.

How Often Should You Check Tyre Pressure?

The recommended minimum is once a month, plus before any long journey. Tyres naturally lose a small amount of pressure over time. Even a tyre in perfect condition can lose around 1 to 2 PSI per month.

You should also check immediately if:

Your tyre pressure warning light (TPMS) comes on.
The car feels like it's pulling to one side.
Steering feels heavier or less responsive than usual.
You've had a slow puncture or recent kerb impact.

What You'll Need

Checking your tyre pressure requires very little:

A tyre pressure gauge (digital or analogue, both work well).
Access to an air compressor (petrol stations have these, usually for free or a small fee).
Your car's recommended tyre pressure figures.

Many modern petrol station forecourt machines allow you to simply enter your target pressure and they'll inflate or deflate automatically. If you check your tyres regularly at home, a digital gauge costs around £10 to £15 and is a worthwhile addition to your boot.

How to Check Your Tyre Pressure: Step by Step

1. Check When the Tyres Are Cold

Tyre pressure increases as the tyres warm up from driving. For an accurate reading, check before you've driven more than a mile or two, or after the car has been parked for at least three hours.

2. Find the Valve Stem

Each tyre has a small rubber or metal valve stem on the inner edge of the wheel. Remove the dust cap and keep it somewhere safe.

3. Attach Your Gauge

Press your tyre pressure gauge firmly onto the valve stem. You may hear a small hiss of air. Press harder to get a proper seal and a stable reading.

4. Read the Pressure

Your gauge will display the current pressure in PSI or BAR. Note it down.

5. Compare to Your Recommended Pressure

Check the reading against your car's recommended pressure (see the door sill sticker or owner's manual). If it's low, you need to add air. If it's too high, you'll need to release a small amount.

6. Replace the Dust Cap

Once you're done, put the valve cap back on. It keeps dirt and moisture out of the valve, which can cause slow leaks over time.

7. Repeat for All Four Tyres

Don't forget to check all four, and your spare if you have one. It's easy to only check the ones that look flat, but pressure loss isn't always visible to the naked eye.

Important

A tyre can be significantly underinflated without looking visibly flat. Always use a gauge. Eyeballing it isn't reliable.

How to Inflate Your Tyres

Most drivers use a petrol station forecourt machine. Here's how:

Remove the valve cap from the tyre you're inflating.
On the machine, enter your target pressure (in PSI or BAR, depending on what the machine uses).
Attach the air hose firmly to the valve stem.
The machine will inflate and stop automatically when the target pressure is reached.
Check the reading, replace the dust cap, and repeat for each tyre.

If you're using a separate gauge and compressor at home, add air in short bursts, checking the pressure after each one to avoid overfilling.

Releasing excess pressure. If a tyre is overinflated, use the small pin inside your gauge or the end of a pen to briefly depress the centre of the valve. Release air in short bursts and check frequently.

What if My Tyres Keep Losing Pressure?

If you find yourself topping up the same tyre repeatedly, there's likely an underlying cause worth investigating:

A slow puncture. A nail, screw, or piece of glass embedded in the tread can cause a gradual leak. Take the tyre to a garage for inspection. It may be repairable.
A faulty valve. The valve stem can degrade over time and allow air to escape. A new valve is inexpensive.
A damaged bead. The seal between the tyre and the wheel rim can be compromised by a pothole or kerb strike. This usually requires a garage visit.
Temperature changes. Cold weather causes tyre pressure to drop (roughly 1 PSI for every 10°C drop in temperature). This is normal and not a sign of a puncture.

Tyre Pressure and the Law

In the UK, driving on tyres in a dangerous condition, including tyres that are significantly underinflated, is an offence. You could face a fine of up to £2,500 and three penalty points per tyre. On top of that, an insurer may reduce or reject a claim if an accident is found to have been caused by poorly maintained tyres.

The minimum legal tread depth in the UK is 1.6mm across the central three-quarters of the tyre. While this is separate from pressure, it's worth checking your tread at the same time you check your pressure. A 20p coin is a handy guide: insert it into the tread groove. If the outer band of the coin is visible, your tread is below the legal limit.

Frequently Asked Questions

What happens if I drive on underinflated tyres?

Underinflated tyres generate excess heat, which increases the risk of a blowout, particularly at motorway speeds. Handling and braking distances are also affected. It's not a risk worth taking.

Can I check tyre pressure with the car running?

Technically yes, but it's better to check with the engine off and the tyres cold for the most accurate reading.

What does the TPMS warning light mean?

TPMS stands for Tyre Pressure Monitoring System. When the light comes on (usually a cross-section of a tyre with an exclamation mark), one or more tyres are significantly below the recommended pressure. Check all four as soon as it's safe to do so.

Is it bad to overinflate tyres?

Yes. Overinflated tyres have a smaller contact patch with the road, reducing grip. They also wear faster in the centre of the tread and are more vulnerable to damage from potholes and kerbs.

Should I inflate my tyres to the maximum pressure shown on the sidewall?

No. The pressure on the tyre sidewall is the maximum the tyre can handle, not the recommended running pressure. Always use the pressure specified in your car's handbook or door sill sticker.

Does tyre pressure affect fuel consumption?

Yes, meaningfully. Underinflated tyres create more rolling resistance, which makes your engine work harder. Keeping tyres properly inflated is one of the easiest ways to improve fuel economy.