MOT Testing Criteria For Car Windscreen Damage and Scratches

Author: Rob Mobberley


How to remove scratches from glassWill my car fail its MOT if it has damage or scratches on the windscreen? What will cause a fail and what is acceptable for a pass?  What are the options for remedy or repair of scratches and damage?

These are questions that are frequently asked by car owners facing their next MOT and unsure if they should have their windscreen repaired or replaced prior to their test.

In this post we will look at the current testing criteria for windscreens and what is and is not likely to result in an MOT failure.

There are a number of types of “damage” that will result in an MOT failure if they fall within the shaded zone of the diagram below. These include chips, cracks, stickers or significant scratches that are 10mm or bigger.

Obviously if it is just a screen sticker within or protruding over the area then the owner should be given the immediate opportunity to remove it. The other types of damage will need to be removed or repaired to enable the windscreen to pass inspection.

MOT Windscreen Inspection Criteria for Damage and Scratches

Outside of Zone A but contained within Zone B your screen will fail its inspection only if the damage is of the size 40mm or over.

If your windscreen has been repaired these repairs will be inspected to the same test criteria as original unrepaired screen. The repair will be judged solely on the basis of whether they allow clear vision.

An ‘invisible’ or barely detectable repair that is finished flush to the rest of the glass, does not count as “damage” even if it exceeds the limit on damage allowed in the test. But it does have to be a good repair and as mentioned above barely detectable.

Light surface scratches on your windscreen is not to be considered as “damage”, unless it is an area of concentrated scratching i.e scratches caused by the prolonged use of a defective wiper blade. If the scratched area obscures vision and is of or over the size limits of Zone A or B than it will be considered as a reason for the screen to fail the MOT.

Cost Effective Windscreen Repair Options

On average the cost of repair of windscreen damage is 70% less than the cost of screen replacement and depending on your insurance cover you may be able to get the repairs done for free and without impact on your no-claims bonus. If this is not an option there are cost effective options available to you:

  1. Chips/Cracks – these can be repaired although normally only if up to the 10mm in length in Zone A, 25mm long if in the swept area around Zone A and up to 40mm if on the Zone B swept area. For trucks it is slight different and we have heard of cracks as long as 150mm being repaired in HGVs. It us advisable to employ the services of a professional firm to repair chips or cracks.
  2. Scratches – these can be repaired by either employing the service of a glass repair company or using a DIY windscreen scratch repair kit. You might find our previous blog post on How to use glass scratch remover to remove scratches from your windscreen informative on how these these kits work and how to use them.

Hopefully this article will have given you the information you were looking for in relation to any damage or marks you have on your screen in the run up to your MOT.

Your Turn: 

What experiences have you had with your windscreen and MOT test? Have you managed to save ££’s by repairing your own screen? Please share your experiences in the comments.


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  • Driving Schools Dartford

    Very useful post, thanks for sharing.

  • Blackcircles

    That’s a very informative article. Thanks for posting.

  • Callum Pragnell

    To prevent such things like this happening, it is better to invest in the appropriate equipment before hand to enforce the well being of your car (sufficient wiper blades etc). This will decrease the risk of damage and therefore save you time and money in the long run.

  • Marc Hone

    Useful info, thank you.

    I disagree that most damage is avoidable, especially when its due to other drivers neglect with stones coming out of off-road driven tyres, construction trucks that carry dirt and gravel and bring the loose stones that come off whilst they are driving straight behind into the cars or onto the road to be picked up and then into other cars.
    I agree having working wipers is a must but not due to the scratches it can cause but for wet weather vision primarily.

    I’m amazed at how many chips cars sustain from the seemingly unavoidable damages or is there a practical, reasonable way for me to avoid this? I find waxing the car regularly (monthly) helps protect the paintwork (apart from the door dings from ‘those!!’ people).

  • Simon Bowers

    Great post, can’t actually believe there aren’t more of these out there for similar MOT issues, would save a lot of people hassle.

    In the past when I’ve needed my windscreen repairing I’ve used they’ve not let me down yet, but I’ll certainly be able to save a lot of time and hassle referring back to your guide!