Windscreen chip and crack repair: cost, MOT rules and when to replace
Most small windscreen chips can be repaired for roughly £40 to £80, and many comprehensive policies cover the repair with little or no excess. It pays to act quickly: temperature changes and vibration can turn a chip into a crack, which usually means a full replacement costing roughly £150 to £500 or more.
For the MOT, damage larger than 10mm in the driver’s line of sight fails, as does damage larger than 40mm elsewhere in the area swept by the wipers. This guide explains the rules, when to repair or replace, what it costs, and how insurance can help.
Last updated 29 September 2026. MOT size limits were checked against several UK sources and GOV.UK’s MOT guidance. Costs are typical ranges and vary by car and provider.
Key takeaways
- In Zone A, the 290mm-wide strip in front of the driver, damage over 10mm fails the MOT.
- Elsewhere in the wiper-swept area, damage over 40mm fails the MOT.
- A small chip repair typically costs roughly £40 to £80 and is often covered by comprehensive insurance.
- Replacement usually costs roughly £150 to £500 or more, and may require camera recalibration on newer cars.
- A properly repaired chip normally passes an MOT.
- Repair chips quickly, because they can spread into cracks within days.
In this guide
- What are the MOT rules for windscreen chips and cracks?
- Should you repair or replace a damaged windscreen?
- How much does windscreen repair or replacement cost?
- Will insurance pay for a windscreen chip?
- What to do as soon as you get a chip
- How does a windscreen chip repair work?
- Is it illegal to drive with a chipped or cracked windscreen?
- How to stop chips turning into cracks
- Frequently asked questions
- Sources and further reading
What are the MOT rules for windscreen chips and cracks?
The MOT divides the windscreen into zones, and the size of the damage and where it sits both matter. Only the area swept by the wipers is tested.
| Area | Maximum damage | Result if larger |
| Zone A: a 290mm-wide strip centred on the steering wheel, within the wiper-swept area | 10mm | MOT fail (major defect) |
| The rest of the wiper-swept area | 40mm | MOT fail (major defect) |
| Outside the wiper-swept area | Not tested unless it affects the driver’s view | Normally no effect on the MOT |
As a rough guide, 10mm is about the size of a pencil eraser, and 40mm is about two £2 coins side by side. Smaller damage that does not affect the driver’s view is normally recorded as an advisory rather than a failure. The full rules are on GOV.UK’s Getting an MOT page.
Should you repair or replace a damaged windscreen?
| Situation | Usually | Why |
| A small chip that has not spread | Repair | It stops the damage spreading and restores strength |
| Several chips close together | Often replace | Testers may treat close chips as one damaged area |
| A crack running across the screen | Replace | Cracks weaken the glass and usually cannot be repaired reliably |
| Damage at the edge of the screen | Often replace | Edge damage can spread quickly and reduces the strength of the screen |
| Damage in Zone A that would still be over 10mm after repair | Replace | The repair mark could still fail the MOT |
| A very small chip outside Zone A | Repair | Cheap and quick, and stops it becoming a crack |
A properly repaired chip normally passes an MOT, provided any remaining mark is within the size limit for its zone. A garage or windscreen specialist can tell you which option applies once they have seen the damage.
How much does windscreen repair or replacement cost?
| Option | Typical cost | Notes |
| Professional chip repair | Roughly £40 to £80 | Often free with comprehensive insurance |
| DIY repair kit | Roughly £5 to £15 | Suits only very small chips, and may not be accepted at an MOT |
| Windscreen replacement | Roughly £150 to £500 or more | Depends on the car. Excess often applies |
Modern cars with cameras or driver-assistance systems mounted on the windscreen may need those systems recalibrated after a replacement, which can add to the cost. Prices vary by car, location and provider, so get a quote and ask what it includes.
Will insurance pay for a windscreen chip?
Many comprehensive policies include windscreen cover, and a repair is often covered with little or no excess, while a replacement usually carries an excess. Some insurers do not count a windscreen claim against your no claims discount, but this varies, so check your policy. Our guide to windscreen cover insurance explains how it works, and our explainers on no claims bonuses and excess will help you understand the small print.
Some insurers ask you to use their approved repairer, so contact them before booking anywhere else.
What to do as soon as you get a chip
- Avoid slamming the doors and driving on rough roads until it is fixed.
- Cover the chip with clear tape to keep dirt and moisture out, if you can do so safely.
- Take a photo with a coin next to the chip to show its size.
- Avoid blasting the screen with very hot or very cold air, and never pour hot water on it, as sudden temperature changes can make chips spread.
- Book a repair as soon as you can. Chips often turn into cracks within days, especially in cold weather.
- Check your insurance policy for windscreen cover before booking.
How does a windscreen chip repair work?
A technician cleans the chip and removes any loose glass, injects clear resin into the damage, cures it with UV light, and polishes the surface smooth. It typically takes 20 to 30 minutes, and many providers can do it at your home or work. A repair is not invisible and you may still see a faint mark, but it stops the damage spreading and restores much of the screen’s strength.
Is it illegal to drive with a chipped or cracked windscreen?
There is no single rule that says every chip is illegal. The MOT sets the size limits above. Separately, drivers must be able to see the road clearly, so damage that obstructs your view can be treated as an offence whether or not your MOT is due. Penalties can include a fine and penalty points, and an insurer may take a dim view of a claim if damaged glass contributed to an accident.
If you are not sure whether your damage is a problem, treat anything in the driver’s line of sight as urgent.
How to stop chips turning into cracks
- Keep a safe distance from lorries and vehicles on gravel or loose surfaces
- Keep the windscreen and wipers clean, and replace worn blades. See when to change your wiper blades
- Use proper de-icer or a screen cover in winter, not hot water
- Fix chips before your MOT. Our guide on how to avoid failing your MOT lists other quick checks
- Check your MOT history on GOV.UK to see any past windscreen advisories
Frequently asked questions
Can a repaired windscreen chip pass an MOT?
Usually yes. A clean resin repair normally passes provided the remaining mark is within the size limit for its zone, which is 10mm in the driver’s line of sight and 40mm elsewhere in the swept area.
What is Zone A on a windscreen?
Zone A is a 290mm-wide strip centred on the steering wheel, within the area swept by the wipers. It is the part the driver looks through, which is why the MOT limit there is stricter.
How long does a windscreen chip repair take?
Typically 20 to 30 minutes. Many providers offer a mobile service and will come to your home or workplace.
How long can I drive with a chip in my windscreen?
You should repair it as soon as you can. Chips can spread into cracks within days, especially in cold weather, and a crack usually means a replacement.
Are DIY windscreen repair kits any good?
They can work on very small chips, but professional resin and UV curing are generally stronger and clearer, and a DIY repair may not be accepted at an MOT. Use them only for minor damage.
Does a windscreen claim affect my no claims discount?
It depends on your insurer. Many treat windscreen claims differently from other claims, but check your policy documents to be sure.
Can damage at the edge of the windscreen be repaired?
Often not. Edge damage can spread quickly and weaken the screen, so it usually needs to be assessed by a specialist and is more likely to need a replacement.
Do I need my cameras recalibrated after a windscreen replacement?
If your car has a camera or driver-assistance system on the windscreen, it may need recalibrating after a replacement. Ask the provider whether it is included in the price.
Sources and further reading
- GOV.UK: Getting an MOT
- Fastlane Autocare: Cracked windscreen law and the MOT
- WindscreenReplacementCost.com: Windscreen MOT rules
- CarOwl: Windscreen chip and crack repair
About this guide: Rooster is a UK car insurance provider. This guide is general information for UK drivers and is not a substitute for advice from a qualified windscreen technician or MOT tester. Costs and rules can change.
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