Will a small crack in the windscreen fail the MOT?

In zone A, damage larger than 10mm is a fail. In the rest of the area swept by the wipers, damage larger than 40mm is a fail. Smaller damage outside zone A can be an advisory.

How do I know if my windscreen crack will cause a failure?

Zone A is a 290mm-wide band centred on the steering wheel. Damage there over 10mm fails. Damage over 40mm in the rest of the swept area also fails.

Can I drive with a cracked windscreen before the MOT?

It is legal to drive with a cracked windscreen. Damage over 10mm in zone A, or over 40mm in the rest of the swept area, will fail the MOT.

What if I fix the crack after the MOT test?

Repair or replacement before the test removes that defect from the inspection. A repair after a fail means a retest.

Will My Car Fail an MOT Due to a Cracked Windscreen?

It depends on the size and where the damage sits. The tester measures the windscreen in two zones:

Zone A: a 290mm-wide area centred on the steering wheel. Damage over 10mm fails.
Rest of the swept area: the glass cleared by the wipers. Damage over 40mm fails.

Damage of 10mm or less in zone A, or 40mm or less in the rest of the swept area, is not an automatic fail. The tester can still record an advisory. Damage outside the area swept by the wipers is judged on whether it affects the driver's view.

Before the test

A small chip can often be filled. A crack that is already over the limit usually needs a new windscreen. Some insurance policies include windscreen cover. That is a policy question, not part of the MOT record.

The MOT check shows earlier test results for the registration, including any windscreen advisories that were recorded. It does not book a test.

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