Tyre tread depth: the UK law and the 20p test
The legal limit is 1.6 mm, but performance drops well before that.
Published 13/10/2026
The legal minimum in the UK is 1.6 mm across the central three quarters of the tread, around the whole tyre. Each illegal tyre can mean a fine of up to £2,500 and 3 penalty points.
The 20p test
Put a 20p coin into the main grooves. If you can see the outer band of the coin, the tread may be close to the limit.
Why replace earlier
Wet braking distances grow quickly below 3 mm. Many experts recommend replacing at 3 mm, especially before winter.
Related advice
Winter car checklist
Get your car ready for cold, dark and wet months.
Summer road trip checklist
Checks to make before a long summer journey.
Servicing an electric or hybrid car
Fewer moving parts, but they still need regular checks.