Compare cars

How does one car compare with another at the MOT?

Pick any two models. We put their real MOT results side by side at the same mileage: how often each passes, and which parts each one fails on more often than the other. 741 models and generations to choose from.

Cars like the Audi A4 B9

Popular comparisons

Sister cars share a platform, so their parts should fail alike; a gap between them points to how the car was specified, tuned or built. Rivals are the same size and age from other makers.

Built on the same platform

Rivals

How we compare cars

Real MOT results. Every figure comes from the DVSA's record of MOT tests on cars in Great Britain and Northern Ireland. We count each MOT once, including any retest within 14 days.
Same mileage only. Cars are compared within the same mileage band (for example 50,000–60,000 miles), so a high-mileage car is never measured against a low-mileage one.
Enough tests on both sides. A mileage band is only compared when each car has at least 1,000 MOTs in it.
Only clear differences. A part is listed only if it fails on at least 1 in 200 MOTs on the worse side, at least one and a half times as often as on the other car, and the gap is far too big to be chance (the two 99.9% confidence ranges don't overlap). It also has to hold in at least half of the mileage bands we could compare.
Like for like. We leave out equipment that depends on when a car was built rather than how it lasts, such as tyre pressure monitors and stability control, which became compulsory on new cars in November 2014.
Similar cars are chosen by hand. On results pages we compare each model with two to four others of the same size and age, chosen by segment and era, never by picking cars that fail alike.
What it isn't. These are differences in real-world MOT results, not engineering verdicts. Owner mix differs between models: some are more often taxis, first cars or rural cars.

MOT records: DVSA MOT history, which contains public sector information licensed under the Open Government Licence v3.0. See also how complete our MOT data is.