How do I find my tyre size?

The most reliable place to find your tyre size is printed directly on the tyre's sidewall, as a code like 205/55 R16. The first number (205) is the tyre's width in millimetres, the second (55) is how tall the sidewall is compared to that width, and the last number (16) is the wheel size in inches. There are usually a couple more numbers and a letter after that, which relate to how much weight and speed the tyre is rated for - not something you usually need to worry about day to day.

You'll usually also find the manufacturer's recommended size on the sticker inside the driver's door pillar or fuel flap, or in the handbook - this is the size the car was designed for, whereas the sidewall shows what's actually fitted right now. They should normally match, but if a previous owner has changed the tyre size, they can differ, so it's worth checking both if you're not sure which to trust.