Four checks, one verdict
Every car gets four sub-scores, each 0 to 100. They're blended into a single score, weighted by how much each one should matter to a buyer or owner.
1 · Reliability
How cars of this exact make, model and age actually perform at MOT: first-time pass rates and what fails when they fail. Computed from the full national test history, not a sample.
2 · Mileage integrity
Every MOT logs the odometer. We line the readings up in order. If mileage ever falls, or jumps implausibly, the car is flagged as possibly clocked. A clean, consistent sequence scores full marks.
3 · Running costs
What the car costs to keep: road tax band, estimated annual fuel spend at typical mileage, and its insurance group relative to its class.
4 · Compliance
Whether it drives free through the ULEZ and every UK clean-air zone (by emissions standard), and whether it has open safety recalls.
The verdict thresholds
Three states, never a fourth. The thresholds are editorial judgement, published here so you can disagree with them intelligently.
What our data cannot see
Public data has hard limits, and pretending otherwise would make every verdict dishonest. We cannot see:
That's why every verdict page recommends a paid full history check before you hand over money for a specific car. Those checks cover the private databases we can't.