What is the legal minimum tread depth in the UK?

The legal minimum tread depth in the UK is 1.6mm across the central three-quarters of the tyre, around the entire circumference. Driving with less than 1.6mm can result in a £2,500 fine and 3 penalty points per tyre.

When should I actually replace tyres?

While 1.6mm is the legal minimum, most tyre experts recommend replacing at 3mm. Wet braking distances increase significantly below 3mm. Many breakdown services and tyre retailers recommend the 3mm threshold.

How do I measure tread depth?

Use a tread depth gauge (available cheaply from car parts shops) or a 20p coin. Insert the coin into the main tread groove — if you can see the outer band of the coin, your tread is below 3mm and replacement should be considered.

What causes uneven tyre wear?

Incorrect wheel alignment causes wear on one edge. Underinflation wears both edges while overinflation wears the centre. Worn suspension components (shock absorbers, bushes) cause patchy wear. Regular alignment checks and correct pressures prevent premature and uneven wear.

How do I check tyre tread depth at home?

Use a tyre tread depth gauge (available for a few pounds from motor factors) for an accurate reading. Alternatively, the 20p coin test works: insert a 20p coin into the tread. If you can see the outer band of the coin, the tread may be below the legal limit.

CarCalcs

Tyre Wear Calculator

Estimate remaining tyre life based on current tread depth and mileage.

Current Tread Depth

New tyres are typically 7-8mm

Miles Since Tyres Were New

Total miles driven since fitting new tyres

How We Calculate This

Calculates the wear rate (miles per mm of tread) from your mileage and tread worn so far, then projects remaining life.

Formula

Wear rate = Miles driven / mm of tread worn
Miles remaining = Wear rate x (Current depth - 1.6mm)

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Last updated: February 2026

All calculations are estimates. Actual figures may vary based on driving conditions, vehicle specifications, and other factors.