A windscreen chip or crack can fail an MOT in the UK if it affects the driver’s view of the road. Zone A damage is judged more strictly, and even smaller chips can become serious if they spread across the screen.
A windscreen chip can fail an MOT if the damage is more than 10mm in Zone A, or more than 40mm elsewhere in the windscreen’s swept area, where it significantly affects the driver’s view of the road.
A small chip outside the driver’s main viewing area may still pass, but it can worsen later. Repairing chips early is usually cheaper and safer than waiting until the screen cracks.
The tester is checking whether the driver has a clear view through the windscreen. That means the chip size, position, distortion, repair quality, wiper-swept area and anything else blocking vision all matter.
A chip is not judged only by how annoying it looks. It is judged by whether it affects the driver’s ability to see the road clearly.
The MOT visibility check is about whether the driver has a clear view of the road.
Damage over 10mm in Zone A can fail because this is the driver’s main viewing area.
Damage over 40mm elsewhere in the wiper-swept area can fail if it affects the driver’s view.
Cracks are more likely to become a problem because they can run across the screen.
Several smaller marks may still affect visibility when grouped together.
A repair can still be an issue if it leaves distortion, cloudiness or marks in the driver’s view.
Wipers, washers, tinting, stickers, mounts and decorations can also affect the MOT result.
Zone A is the main area directly in front of the driver. It sits within the wiper-swept area, is 290mm wide, and is centred on the steering wheel.
Damage here is treated more seriously because it can directly interfere with the driver’s forward view.
Think of Zone A as the part of the windscreen you rely on most when judging traffic, pedestrians, road markings and hazards ahead. Even a small chip can be distracting if it sits right in that line of sight.
That is why the allowed damage size is smaller in this area.
The same chip can be judged differently depending on where it sits.
Main driver viewing area. Damage over 10mm can be an MOT issue.
The part cleared by the wipers. Damage over 40mm can be an issue.
Still worth repairing, but it is judged differently from the main viewing area.
Chips and cracks behave differently, especially with weather, vibration and potholes.
A small chip may pass if it is outside Zone A, not spreading and does not significantly affect the driver’s view.
A star-shaped chip can spread into cracks, especially with cold weather, potholes and vibration.
A crack is more concerning than a small chip because it can spread and may obstruct vision across the swept area.
Damage that reaches or starts near the edge of the screen can be harder to repair and may require replacement.
Usually yes. Small chips can often be repaired quickly if dealt with early. Once cracks spread, replacement is more likely.
A good repair should be flush or barely noticeable and should not distort the driver’s view.
Long cracks, multiple chips, edge damage or damage in critical viewing areas may need a new screen rather than a simple repair.
If the car has cameras or driver-assistance systems attached to the screen, calibration may also be needed after replacement.
The right answer depends on the size, position, type of damage and repair quality.
Small chips that have not spread are often suitable for resin repair.
Long cracks, multiple chips, edge damage or damage in critical areas may need a new screen.
Temperature changes, potholes and body flex can turn a chip into a crack.
Many UK policies include windscreen repair or reduced-cost replacement cover.
These checks help catch windscreen and visibility problems before test day.
Look for chips, cracks, star breaks or scratches directly in front of the driver.
See whether the damage sits inside the area cleared by the wipers.
Look carefully at the area centred on the steering wheel.
If a crack has grown since it first appeared, repair or replacement is more urgent.
Make sure the wipers clear properly and the washers spray enough fluid.
Remove stickers, sat-nav mounts, air fresheners or objects blocking the driver’s view.
A windscreen chip is only one visibility issue. The driver must be able to see clearly.
Wipers that are missing, insecure, damaged or smearing badly can fail.
Wiper MOT guide →Washer jets must spray enough fluid to clear the screen when needed.
Washer MOT guide →Mounts, stickers, dash items or decorations can fail if they obstruct the driver’s view.
Heavy tinting or discolouration can affect forward visibility.
Damaged, missing or badly positioned mandatory mirrors can affect the MOT.
Mirror MOT guide →Scratches, smearing or screen damage can become a problem if the driver’s view is affected.
Costs vary by vehicle, insurance cover, glass type and whether cameras or sensors are fitted.
Usually the cheapest option if caught early and the damage is suitable for repair.
More expensive than a chip repair, with cost depending on the vehicle and glass type.
Can cost more because cameras or driver-assistance systems may need calibration.
A chip or crack should not be ignored when viewing a used car. It may be a small negotiation point, or it may mean the screen needs repair before the next MOT.
Check whether the damage is in Zone A, whether it has been repaired properly and whether old MOT history mentions visibility advisories.
Also check wipers, washer jets, mirrors and any camera equipment mounted behind the screen. On newer vehicles, replacing the windscreen may involve calibration.
Helpful next reads: used car inspection checklist and questions to ask when buying a used car.
These are common issues noticed during MOT preparation and used car checks.
A small chip can matter more if it sits in the driver’s main view.
Cold weather, heater use, potholes and vibration can make damage spread.
A repair can still be distracting if it leaves haze or distortion in Zone A.
Bad wipers can make marks, cracks and dirt more distracting in rain.
A mount placed badly can become an obstruction even if the screen is undamaged.
Some windscreens cost more to replace because camera calibration may be needed.
If the chip is in front of the driver, repair it before the MOT rather than hoping it passes. Even if it is small now, a spreading crack can quickly become a failure or require a full windscreen replacement.
For a full pre-test checklist, read how to prepare for an MOT test.
A clean, undamaged windscreen still needs working wipers and washers. The tester needs to see that the driver can maintain a clear view in normal use.
Check the simple items before test day because they are avoidable failures.
Common questions about Zone A, cracks, repairs, wipers and driver visibility.
Yes, if it is in the driver’s main viewing area and large enough to significantly affect visibility.
Damage over 10mm in Zone A or over 40mm elsewhere in the swept area can be an MOT issue if it significantly affects the driver’s view.
Yes, if the repair is flush, barely noticeable and does not distort or interfere with the driver’s view.
Yes. Cracks that obstruct vision, spread through the swept area or exceed the relevant limits can fail.
Usually yes, especially if it is in front of the driver, spreading or likely to get worse.
Yes. Temperature changes can cause chips to spread into larger cracks.
Yes. Wipers and washers can fail if they do not give the driver a clear view through the windscreen.
Yes, if it significantly obstructs the driver’s view of the road.
Motor Vehicle Expert publishes practical UK-focused vehicle diagnostics, maintenance, MOT, warning light, used car and repair cost guidance based on common driver questions and real-world garage situations.
