How the score works

Enter a registration and Bonafied reads that vehicle's full MOT history from the official government record, then distils it into one clear score. This page explains what goes into that score, and what deliberately doesn't.

What's behind the score

The scale and the tiers

Every eligible vehicle gets one score from 0 to 100, and the score places it in one of three tiers:

• Hidden Gem 90–100 — A clean history is no accident.
• Solid Find 70–89 — Sound, with a story you can read.
• Proceed with Care 0–69 — Worth understanding before you commit.

A car needs enough MOT history to be judged fairly. When there is too little on record — a car under three years old, for example, has no MOT history at all — we say so and withhold the score rather than bluff a number.

What the score is not

The score is an MOT-history assessment only. It is not a valuation, and it is not a substitute for an independent vehicle history check, a physical inspection, or a professional mechanical appraisal. Write-off categories, outstanding finance and theft markers are not part of MOT data, which is why we always recommend a full history check before any purchase.

What changed on 6 October 2026

One advisory used to cost a clean car far more than it should. A run of clean tests earns a car credit, and a single advisory wiped out most of that credit, so a tyre close to the legal limit could cost a perfect record almost 17 points. Now a blemish steps the credit back, the way a claim affects a no-claims bonus, rather than starting again from nothing. How far it steps back depends on what was found, and clean tests afterwards earn it back. A clean record still scores 100.

We also now count a finding once per test. Testers type one line per tyre or brake pipe, so the same advisory could be charged several times at one test. Each finding now carries about 30% more weight than a single line did, which keeps the overall scale where it was, so what a car is charged depends on what was found rather than how it was typed.

Between them, these changes moved most scores a little. About two in five went up and about half went down, by 2.6 points on average. The largest rise was 12 points and the largest fall 11.

What changed on 5 October 2026

We changed how the score is worked out in five ways. About one car in five now scores higher, and about one in eight scores lower. Most moves are a point or two. Here is each change, which way it moves a score, and why we made it.

Two changes that raise scores

A short, clean record can now reach the top of the scale. Until now a spotless record was held back by the car's age: only a car well into its second decade could reach 100, however clean its tests. Now a car whose every test is clean, over about two years of testing or more, can score 100. A car whose last five tests are all clean also gets full credit for that run, even with a blemish earlier on. The blemish itself still counts. How long the record is still shows on the page beside the number, where we list how many tests there are and how much of the car's life they cover.

A long gap between tests is no longer counted twice. We already pull a score towards the middle when part of a car's history is missing, because missing years are unknown rather than bad. We were also taking points off for the same gap. We have stopped. A test that was a few months late is still a dated fact, and still costs a little.

Together these raise about 9,400 of the 45,000 cars we score, by a point and a half on average and seven at most.

Three corrections that lower scores

These were mistakes in how we read the test record. We were missing three kinds of advisory, so cars that had them scored higher than they should have.

Thin brake pads, in the older wording. MOT testers' standard phrases changed some years ago. We were charging "brake pads wearing thin" in the current wording and missing it in the older one. Very few cars are affected, because most of those entries are old enough to have faded.

Play in the steering rack. We were missing this advisory altogether. It now counts like any other advisory about steering.

A corroded or covered brake pipe. We were treating "brake pipe corroded, covered in grease or other material" as a note that the tester couldn't see something, and ignoring it. It is an advisory about the brakes, and it now costs a little, fading with time like the others. Because the wording doesn't say whether the pipe was corroded or only covered, it doesn't end a run of clean tests.

Together these lower about 5,500 cars, by a point and a half on average. The largest fall is fourteen points, on a car with this advisory recorded many times over.

What did not change

The tier boundaries are where they were. Nothing about a car's record is judged more harshly than before unless it is one of the three corrections above. A failed test still costs what it did, and so does a mileage reading that goes backwards.

If your car's score moved

The reasons are listed under the score, as before. A score card downloaded before 5 October 2026 shows the score as it was that day, and carries its date. Its code opens the score as it stands now.

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