How to Find Your Tyre Size and Pressure Without Guessing

You're at a tyre fitting centre. The person behind the counter asks what size tyres you need. You look at your phone, then at the ceiling, then back at them. "I'll just get the same as what's on there," you say, which is the right answer, delivered with the wrong level of confidence.

This is the experience for most UK drivers. Tyre size is one of those pieces of information that lives somewhere, in the handbook, on the door frame, on the tyre sidewall, but never quite where you are when you need it.

Where your tyre size lives

There are four places to find your tyre size, in order of convenience:

• The tyre sidewall itself, a sequence like 205/55 R16 appears moulded into the rubber. Width in mm, then aspect ratio as a percentage, then rim diameter in inches.
• The door frame sticker, inside the driver's door or on the B-pillar, often alongside tyre pressure information.
• The fuel cap, some manufacturers print tyre specs here, particularly pressure information.
• Your owner's handbook, the definitive source, but rarely within arm's reach when you need it.

The most common tyre size in the UK is 205/55 R16, but there are hundreds of variations, and fitting the wrong size affects handling, fuel efficiency and MOT compliance.

Reading the tyre pressure

Tyre pressure is measured in PSI (pounds per square inch) or BAR. Your car will have two recommended pressures: one for standard load and one for when the car is carrying more passengers or luggage. Front and rear pressures can also differ.

Michelin note that a tyre under-inflated by just 1 BAR (14.5 PSI) increases rolling resistance enough to cost roughly one full tank of fuel per year in wasted consumption, and reduces the tyre's grip and braking performance simultaneously.

Kwik Fit recommend checking tyre pressure at least once a month, and always before longer journeys. Tyres typically lose up to 2 PSI per month naturally, even with no puncture or damage.

The most common tyre size in the UK is 205/55 R16, but there are hundreds of variations. Fitting the wrong size affects handling, fuel economy, and MOT compliance.

Kwik Fit tyre guidance

The simpler approach

All of the above is useful to know. But it requires you to be near your car, or have your handbook, or remember to check before you go to the garage.

When you add your car to Revn using your registration plate, the DVLA integration surfaces your vehicle's tyre size, fuel type, and engine oil spec automatically, no handbook required, no searching the door frame in the dark. It's stored in your account, accessible any time, from your phone.

→ The true annual cost of running a car in the UK, and where you can save

The tyre size question is a small thing, until it isn't. Arriving at a garage without knowing it means relying on whoever's serving you to get it right. Your handbook knows the spec your manufacturer intended, and so does Revn.

References: Kwik Fit tyre guidance · Michelin UK (tyre pressure and consumption) · National Tyres tyre pressure checker