Updated April 2026

How to Read a UK MOT Certificate

A UK MOT certificate shows whether a vehicle passed or failed its annual roadworthiness inspection, lists all defects by severity (dangerous, major, minor), records advisory warnings, and logs the odometer mileage. Carlytics has indexed 830 million UK MOT test records, letting you trace any vehicle's full inspection and mileage history.

What does pass or fail mean on an MOT certificate?

Every car over 3 years old in Great Britain must pass an annual MOT test to be driven legally on public roads. The test covers over 100 checks across lighting, brakes, steering, suspension, tyres, exhaust emissions, body structure, and more.

• Pass: The vehicle meets the minimum legal standards. It may still have minor defects and advisories listed on the certificate.
• Pass with advisory notes: The car passed, but the tester noted items that are deteriorating and may fail at the next test. These are not defects yet.
• Fail: The vehicle has one or more dangerous or major defects and cannot be driven legally until repaired and retested.

What are dangerous, major, and minor defects?

Since May 2018, the UK MOT system classifies defects into three severity levels. Understanding these categories is essential when evaluating a used car's history.

How should you interpret advisory items?

Advisory items are early warnings. They indicate components that are wearing but have not yet reached the failure point. When buying a used car, advisories tell you what will need attention soon.

• Brake pads wearing thin: Budget EUR 150–400 for replacement within the next 10,000 miles
• Tyre close to legal limit: New tyres needed soon, EUR 60–200 per tyre depending on size
• Corrosion on body or subframe: The most concerning advisory. Structural corrosion is expensive to repair and can make the car unsafe
• Slight oil leak: May be minor, but could indicate a failing gasket that will worsen
• Suspension component worn but not excessively: Will likely fail the next MOT if not replaced

How do MOT mileage readings detect odometer rollback?

Every MOT test records the vehicle's odometer reading. Since cars are tested annually, this creates a year-by-year mileage trail. Carlytics plots these readings on a timeline to detect fraud.

• Normal pattern: Mileage increases consistently each year, typically 8,000–12,000 miles annually for a private car
• Rollback detected: Mileage drops between consecutive tests. For example, 85,000 miles in 2022 followed by 52,000 miles in 2023 is definitive proof of odometer tampering
• Suspiciously low annual mileage: A car that suddenly adds only 1,000 miles in a year after averaging 10,000 may have had the odometer disconnected
• Gap in testing: If a car skips an MOT test year, the mileage between readings covers two years, making rollback harder to detect but still visible if the numbers are inconsistent

What should you look for when reviewing a car's MOT history?

• Pattern of repeated defects: The same component failing multiple years in a row suggests a chronic problem the owner keeps patching rather than properly repairing
• Sudden increase in defects: A car that passed cleanly for years then suddenly accumulates multiple defects may be deteriorating rapidly
• Test location changes: A car that suddenly switches from a main dealer to a backstreet garage may be seeking a less rigorous tester
• Mileage consistency: Steady annual increases in mileage are normal and healthy. Irregularities warrant investigation
• Emission failures: Repeated emission failures can indicate engine problems, a failing catalytic converter, or DPF issues that are expensive to fix