Offers now live 
Great deals on selected car tyres
choose our fully fitted service
2,200+ local fitting partners
over 2 million customers served
21 years of exceptional service

Help > Tyres > How do I find my tyre size?

How to read tyre size

The size of a tyre is printed onto the side of the tyre – on the area known as the sidewall. When looking for the size, you will see that it is made up of a series of numbers and letters.

How to find your tyre size

In the above example, each section breaks down as follows:

205 - Width of the tyre in millimetres
55 - Height of the tyre sidewall as a percentage of the width. In this case 55%. Also known as the aspect ratio.
R16 - The diameter of the tyre's inner rim in inches
91 - Load Rating of the Tyre.
V - Speed Rating. Indicates the maximum speed for the tyre when at full load.

You can also use the vehicle registration lookup tool on the Blackcircles.com homepage. This checks the data held by the DVLA to find out what tyre size is appropriate for your vehicle.

When using this tool, we recommend that you double check the size provided against what you currently have fitted to your vehicle as multiple sizes may be recommended dependent on the age and model of your vehicle.

What tyres do I need?

The type of tyres you need depends on wheel size, vehicle type, and driving conditions. Consult your owner's manual or a tyre specialist for guidance.

What tyres are on my car?

To find out what tyres are on your car, check the sidewall of the tyre for a series of numbers and letters that indicate size and type.

What do the tyre numbers mean?

The numbers on the sidewall indicate the width, aspect ratio, and diameter of the tyre, as well as load index and speed rating.

What do the tyre letters mean?

The letters on the sidewall provide information on tyre specifications, such as construction type, intended use, and season suitability.