Tread Depth

Tread depth is how deep the grooves in a tyre’s tread are, measured in millimetres. In the UK a car tyre must have at least 1.6 mm.

Last updated: 19 October 2026

What it means

The Highway Code says cars, light vans and light trailers must have a tread depth of at least 1.6 mm across the central three-quarters of the breadth of the tread and around the entire circumference ^[1]. THINK! and GOV.UK give the same minimum for cars ^[2][3].

Why it matters when you buy

THINK! says driving with less tread can affect grip, braking distance and steering, and that if police find illegal tyres you could receive a £2,500 fine and 3 penalty points per tyre ^[2]. GOV.UK’s vehicle check page describes a fine of up to £2,500, a driving ban and 3 penalty points for driving a vehicle in a dangerous condition ^[3]. The two pages word the penalty differently, so check the current wording.

A worked example

A tyre has a tread 195 mm wide. Three-quarters of 195 mm is about 146 mm, so the 1.6 mm minimum has to be met across the central 146 mm or so, all the way round. A reading of 2.0 mm in the middle is 0.4 mm above the limit. Measure at several points around the tyre.

Illustrative scenario: figures are examples, not quotes, valuations or market prices.

Related

• Tyre pressure and tread depth: what the rules say
• PSI, bar and kPa
• Cold tyre pressure

Sources

1. The Highway Code: Annex 6, Vehicle maintenance, safety and security, GOV.UK. Updated 22 October 2025, gov.uk. Checked 19 October 2026.
2. Vehicle safety checks, THINK!, think.gov.uk. The page shows no date. Checked 19 October 2026.
3. Check your vehicle is safe to drive, GOV.UK, gov.uk. The page shows no date. Checked 19 October 2026.