Is a Cracked Windscreen an MOT Failure?

What the tester is actually checking

The tester is looking at whether the driver can see the road clearly and safely. They check the condition of the windscreen, whether anything is stuck to it or hanging in front of it, and whether the wipers can clear the glass properly.

Damage is judged by its size and by its position. A mark that sits in the area directly in front of the driver is treated much more strictly than the same mark near the passenger side. Cracks that run across the glass, or large areas of chipping, are more likely to be a problem than a single small chip.

The driver's view area and damage size

In general terms, the part of the screen directly ahead of the driver, cleared by the wipers, has the tightest limits. Only a very small amount of damage is tolerated there. Outside that zone, but still within the swept area, a little more is allowed, and damage beyond the wiped area is usually less of an issue.

We are not going to quote exact millimetre limits here, because the current figures should be checked against the official guidance rather than trusted from an article. What we can say is that a crack in the driver's direct view is very likely to be a concern, and a long crack anywhere is worth sorting out regardless of the test.

• Damage straight ahead of the driver is judged most strictly
• Cracks running across the glass are more likely to be marked
• Heavy clusters of small chips can add up to a problem
• Anything that obstructs the view, such as stickers or loose items, can also count against you

Cameras, sensors and modern windscreens

Many newer cars have cameras and sensors mounted behind the glass for lane assist, automatic braking or rain detection. Damage in front of those can affect how they work, and in some cases a replacement windscreen means the system needs to be checked or recalibrated afterwards.

If your car has this kind of equipment, mention it when you book. It affects what is sensible to repair and how a replacement is approached. Not every car is the same, so ask us at the estimate stage.

What to do before the MOT

Check the screen in good light, from the driver's seat, and look at it again from outside. Find every chip and crack, and run a fingernail across them to see whether they have reached the edge of the glass. If you spot anything within your direct view, or a crack that is clearly growing, deal with it before the test instead of hoping for leniency.

Small chips can often be dealt with by windscreen chip repairs, which stop them spreading and may be enough to keep the glass in good order. Larger cracks and damage that has reached the edge usually mean windscreen replacement. Either way, it is far better to find out beforehand than to take a failure and have to return.

• Look at the screen from both inside and outside
• Note any cracks that have reached the edge of the glass
• Clear stickers and dashboard clutter from the driver's view
• Check that the wipers clear the glass cleanly and the washers work

Beyond the test: a safety question

A windscreen does more than keep the weather out. It adds to the stiffness of the body and supports the passenger airbag when it deploys. A cracked screen is weaker, and a crack can spread quickly when you hit a pothole or the temperature drops.

So the sensible question is not only whether it will pass, but whether you are happy driving with it. At Banks of the Tyne in Hebburn we handle windscreen repairs and replacement, so we can look at the glass and tell you where it stands before you go to the test.

Frequently asked questions