The numbers · a guide
How to check a used car before you buy
Picture the advert: good photos, sensible mileage, “drives beautifully”. Nothing about it says that three years ago an insurer paid out on this car and someone bought the wreck back. Nothing about it ever would — that’s not what adverts are for.
This isn’t rare. Of the 100,583 cars on sale right now whose provenance we hold, 1 in 7carries a recorded history flag — a write-off marker, a mileage discrepancy, an import, something the advert didn’t lead with. The check exists because the advert won’t tell you.
The good news: checking a car properly takes about ten minutes, the most useful check is free, and the order matters. Record, mileage, price — cheapest first, so a car that fails early costs you nothing to walk away from.
1. The mileage story — free, and start here
Every MOT’d car’s full test history is public at gov.uk/check-mot-history — free, official, and most buyers never look. You want the odometer column: readings should climb steadily, roughly in line with the advert’s claimed mileage. A reading that goes backwards, a suspicious multi-year gap, or a final-year “slowdown” that conveniently lands under a valuation threshold — each is a question the seller should answer before you travel anywhere.
The advisories tell a story too: three years of “corrosion, not yet dangerous” is a car that’s been ridden, not maintained.
2. The record — the insurers’ register
The things a seller doesn’t volunteer live in the insurance industry’s register: write-offs (Category A/B cars should never be on the road again; N and S can be legitimately repaired but must be priced accordingly), theft markers, scrapped certificates, plate and colour changes, imports. This data isn’t free anywhere — providers pay Experian for it — but it’s cheap: £2–£20 across the market depending on brand and whether an insurance-backed guarantee is attached.
Where our report fits, plainly: £7.99 (first one free), no guarantee — if you want an indemnified check, Autotrader’s £5.95 one has that and we’ll happily point you at it. What ours adds is the third check below, done properly, in the same report.
3. The price — the check almost nobody runs
A car can be exactly what it claims and still cost you £1,500 too much — overpaying is the most common way to lose money on a used car, and no history check catches it. Whether the asking price is fair is its own discipline: we’ve written the method up separately, or paste the listing and get the verdict in ten seconds, free.
Then, and only then: go and see it
Every in-person rule you’ve heard still applies — cold start, panel gaps, tyre wear, V5C name matches the seller. But do the desk checks first. Ten minutes at a keyboard filters out the cars that would have wasted a Saturday, and the ones that pass arrive with a negotiating file attached.
Quick answers
- What does a car history check actually show?
- The insurance industry's register: whether the car has been written off (and in which category), recorded stolen, or scrapped, plus colour changes, plate changes and import/export markers. It does not show service history or current mechanical condition — nothing on a screen does.
- Is the free government MOT check enough?
- It's genuinely useful — the full test and mileage history of every MOT'd car, free at gov.uk. What it can't show is the insurance record: a written-off, repaired car can have a spotless MOT history. The two checks answer different questions.
- Do I need the registration number?
- Yes — every history check keys on the plate. It's usually visible in the advert's photos; if not, ask the seller. A seller who won't share the registration is telling you something.
Looking at a car right now?
Paste the listing — the price verdict is free, and the full check is one click further.