How to check tyre tread depth
UK law says car tyres must have at least 1.6mm of tread. Here's how to check yours with a gauge, the built-in wear bars or a 20p coin.
- Time
- 5 minutes
- Difficulty
- Easy
- Steps
- 6
- Checked
What you’ll need
- Tread depth gauge (or a 20p coin) Search Amazon for tyre tread depth gauge
- Torch, if it's dark
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Safety first
- Driving with tread below 1.6mm is illegal and can mean a fine of up to £2,500 and three penalty points for each illegal tyre.
- Tyres with bulges, cuts or exposed cords are dangerous whatever the tread depth. Don't drive on them.
Step by step
-
Step 1: Know the legal limit
Cars, light vans and light trailers must have at least 1.6mm of tread across the central three-quarters of the tread width, all the way round the tyre. For motorcycles and large vehicles the limit is 1mm.
Next: step 2 -
Step 2: Park safely and turn the wheels
Park on level ground with the handbrake on. Turning the steering wheel to full lock makes it easier to see the front tyres.
Next: step 3 -
Step 3: Use a tread depth gauge
Push the gauge's probe into the main grooves and read the depth. Check several points across the width and around the tyre. Tyres can wear unevenly, and the lowest reading is the one that counts.
Next: step 4 -
Step 4: Or use the 20p test
Put a 20p coin into the main tread grooves. If you can see the outer band of the coin, the tread may be close to or below the legal limit, so get it checked by a tyre centre straight away. Repeat at several points.
Next: step 5 -
Step 5: Check the tread wear indicators
Most tyres have small raised bars moulded into the bottom of the main grooves. When the tread wears down level with these bars, the tyre is at the legal limit and must be replaced.
Next: step 6 -
Step 6: Look for uneven wear
Wear on just the inside or outside edge can mean the wheel alignment is out. Wear on both edges can mean under-inflation, and wear in the centre over-inflation. A tyre centre can check alignment for you.
Tips
- Stopping distances in the wet get longer as tread wears, well before you reach 1.6mm. TyreSafe notes that tyre and safety experts commonly advise replacing tyres at around 3mm.
- Check the inner edges too. They're easy to miss and often wear first.
- Swapping tyres of the same size between axles, if your handbook allows it, can even out wear.
When to call a professional
Go to a tyre centre if your tread is near the limit, a tyre is damaged, or you notice uneven wear. They can measure accurately, replace tyres and check wheel alignment.
Questions people ask
What is the legal minimum tread depth in the UK?
1.6mm across the central three-quarters of the tread, around the whole tyre, for cars and light vans.
Will my car fail its MOT on tread depth?
Yes, tyres below the legal limit are an MOT failure.
How often should I check my tread?
At least once a month and before long journeys, when you check your tyre pressures.
Sources
Checked 9 October 2026. We wrote this guide in our own words, using:
- The Highway Code: Annex 6, vehicle maintenance, safety and security (gov.uk)
- TyreSafe: the complete guide to tyre tread depth (tyresafe.org)
- TyreSafe: the 20p test (tyresafe.org)
- Kwik Fit: tyre tread depth and UK law (kwik-fit.com)
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Printed from howtoguides.uk/guides/how-to-check-tyre-tread-depth/ · Checked 9 October 2026 · General information only. For gas, electrics, structural work, medical, legal or money decisions, use a qualified professional.