What do the car write-off categories mean?

There are four insurance write-off categories in the UK. Cat A means scrap only and the whole car must be crushed. Cat B means the body shell must be destroyed but some parts can be reused. Cat S means structural damage that has been or can be repaired, and the car can legally return to the road. Cat N means non-structural damage, also repairable and road-legal. Cat S and Cat N replaced the older Cat C and Cat D in October 2017.

Is it safe to buy a Cat S or Cat N car?

It can be, if the repair was done properly and the price reflects the history. A Cat S or N car is usually worth roughly 20 to 40 percent less than the same car with a clean history, can cost more to insure and is harder to sell on. Always see the engineer or assessment report, check the repair quality, and ideally get an independent inspection before buying.

Can a Cat A or Cat B car be driven on the road?

No. Cat A must be crushed entirely and Cat B must have its body shell destroyed, so neither can ever legally return to the road. If a seller offers a Cat A or Cat B car as a runner, walk away, it should not be on the road.

Car Write-Off Categories Explained: Cat A, B, S and N

Q: How do I check if a car has been written off?

A vehicle history check shows any recorded insurance write-off and its category. CarMate uses Experian provenance data to flag write-offs, alongside finance, stolen and mileage checks, so you can see the category and date before you buy.

If a car has been in a serious accident, flood or fire, an insurer may declare it a "write-off", meaning it costs more to repair than it is worth. The car is then given a category that tells you how badly it was damaged and whether it can ever go back on the road.

There are four categories. Two mean the car is finished. Two mean it can be repaired and driven again, and those are the ones you need to think hardest about before buying.

The four write-off categories

Category	What it means	Road legal again?
Cat A	Scrap only. The entire car must be crushed, including parts.	Never
Cat B	Body shell must be destroyed. Some parts can be salvaged and reused.	Never
Cat S	Structural damage (chassis, crumple zones) that can be repaired.	Yes, after repair
Cat N	Non-structural damage (cosmetic, electrical, sometimes steering or brakes).	Yes, after repair

Cat S and Cat N replaced the older Cat C and Cat D in October 2017. The old system was based on repair cost, the new one is based on the type of damage. You will still see Cat C and Cat D on older write-offs: roughly, Cat C is comparable to Cat S and Cat D to Cat N.

Cat A and Cat B should never be on the road A Cat A or Cat B car cannot legally return to the road, full stop. If someone is selling one as a driveable car, that is a serious red flag and likely fraud. Walk away.

Cat S: structural damage, repaired

Cat S means the car suffered structural damage, to the chassis, frame or crumple zones, but it was economic to repair. Once repaired, it can be re-registered with the DVLA and driven legally.

The key question is who repaired it and how well. Structural repairs done properly are safe; done badly, they can affect how the car protects you in another crash. Never buy a Cat S car without seeing evidence of the repair and ideally an independent inspection.

Cat N: non-structural damage, repaired

Cat N covers damage that is not structural: panels, lights, bumpers, electrical faults, and sometimes items like steering, brakes or airbags. The chassis is sound. These are often the most sensible used buys of the write-off categories, but "non-structural" does not always mean "cosmetic", so check exactly what was damaged.

Is a Cat S or Cat N car worth buying?

It can be a genuine bargain, or a money pit. The honest trade-offs:

Price. Expect to pay roughly 20 to 40 percent less than a clean equivalent. If the discount is small, the risk is not worth it.
Insurance. Some insurers charge more, or decline a written-off car. Check you can insure it before you buy.
Resale. A recorded write-off stays on the car's history forever and will put off future buyers, so it is harder to sell on.
Repair quality. This is everything. See the engineer's report, photos of the damage, and proof of the repair. Get an independent inspection for anything structural.

The bottom line A well-repaired Cat N car at the right price can be a smart buy. A poorly repaired Cat S car, or any car where the seller is vague about the damage, is one to avoid. The discount has to be big enough to cover the higher insurance, harder resale, and the risk.

How to check if a car has been written off

A write-off is not always obvious from looking at the car, especially after a tidy repair, and a seller is not always upfront about it. The reliable way to know is a vehicle history check, which shows any recorded write-off and its category.

CarMate's History Check uses Experian provenance data to flag write-offs alongside outstanding finance, stolen markers and the full mileage history, and it is backed by a data guarantee from £10,000. So before you view a car, you can already know whether its history is clean, or whether that price looks low for a reason.

For a closer look at when a written-off car is and is not worth it, see our guide on whether a Cat N car is worth buying.