Write-off categories vs insurance groups
Quick answer
They are completely different things. An insurance group is a 1–50 rating of a model, assigned before any car is sold, describing how risky that specification is to insure. A write-off category — Cat A, B, S or N — is a record attached to one individual car after it has been damaged, describing what may legally be done with it. A write-off never changes a car's insurance group.
Why these get confused
Both are insurance-industry classifications applied to cars, both use short codes, and both turn up in the same conversations when you are buying something second-hand. That is where the similarity ends, and the difference is worth stating precisely because it changes what you should do about each.
An insurance group is about a model. The Group Rating Panel rates each new derivative from 1 to 50 based on repair cost, parts prices, performance, safety and security — before a single example is registered. Every Ford Fiesta of the same specification shares the same group, and that number is fixed for the life of the model.
A write-off category is about one car. It is assigned by an insurer after an accident, flood, fire or theft, and it records the extent of the damage and whether the vehicle may return to the road. It is attached to that registration and that VIN only. It says nothing whatsoever about the model.
So a Cat N Fiesta and an undamaged Fiesta of the same derivative sit in the identical insurance group. The category does not re-rate the car — but it does affect its value, its insurability and what some insurers will charge you, which is why the question is worth asking even though the group answer is simple.
The four write-off categories
The current system replaced the older Cat A to D scale in 2017. The key change was replacing categories based on repair cost with categories based on whether the damage was structural — a more useful distinction for anyone deciding whether a car is safe to buy.
Category A — Scrap only
Back on the road: NeverThe entire vehicle must be crushed, including every part. Nothing may be salvaged — not a wheel, not a radio. These cars cannot legally return to the road under any circumstances, and the shell itself must be destroyed.
Category B — Body shell must be destroyed
Back on the road: Never as a whole carThe body shell has to be crushed, but reclaimed parts may be sold on and reused in other vehicles. So a Cat B car never drives again, although its components might. If you are offered one as a running vehicle, something is badly wrong.
Category S — Structural damage, repairable
Back on the road: Yes, once properly repairedReplaced the older Cat C. The car sustained damage to its structure — chassis, subframe, crumple zones or similar — and the insurer judged repair uneconomic relative to the car's value. It can legally be repaired and returned to the road, but structural repair quality is the whole question, and a poor one is genuinely dangerous.
Category N — Non-structural damage, repairable
Back on the road: YesReplaced the older Cat D. No structural damage — the write-off was economic. Often cosmetic damage, water damage, electrical faults or theft recovery. The category covers a wide span, from a scuffed bumper on a cheap car to serious electrical problems, so the specific damage matters far more than the letter.
What a category actually does to your insurance
Three effects, none of which involve the group. Choice narrows — most insurers will cover a repaired Cat N, fewer will cover Cat S, and some decline both. Evidence is requested — engineer's reports, repair invoices and photographs are common requirements, particularly on Cat S. And valuation falls, which cuts both ways: a lower market value can mean a slightly lower premium, but it also means a smaller payout if the car is written off again.
The declaration duty is absolute. If you know the car has a category, tell your insurer. An undisclosed write-off is material non-disclosure, with the same consequences as an undeclared modification — a reduced claim, a refused claim, or a voided policy that leaves you retrospectively uninsured. The obligation is yours even if a previous owner had the damage repaired.
The resale cost nobody mentions
The permanent financial effect of a category is not the insurance — it is the value. A recorded write-off typically sits 20 to 40% below an undamaged equivalent, and that discount never goes away. The record stays on the vehicle's history for good, so you will face the same question from your buyer that you asked your seller.
That cuts both ways. It is why a Cat N car can be genuine value if the damage was cosmetic, the repair is documented and you plan to keep it for years. It is also why buying one as a short-term purchase rarely works out: you pay a modest discount on entry and take a large one on exit.
Checking before you buy
Write-off categories are recorded on industry databases and appear in a paid vehicle history check. They are not shown by the free DVLA vehicle enquiry service, which covers tax, MOT and basic specification — so a history check is worth its small cost on any used purchase. In person, look for mismatched panel gaps, overspray on rubber seals, newer panels on an older car, and a price noticeably below the market for the mileage.
Do the insurance group check at the same time. The group tells you what the car will cost to insure in the ordinary course of things, and the history check tells you whether this particular example carries a complication on top. You can look up the group by registration free, and checking the group before you buy covers the wider pre-purchase sequence. If the car turns out to be an import as well as a category, our guide to imported car insurance groups explains why there may be no group at all.
Frequently asked questions
Are write-off categories the same as insurance groups?
No — they are completely different classifications that happen to both come from the insurance industry. An insurance group is a 1–50 rating describing a model's risk, assigned before any car is sold. A write-off category is a record attached to one individual vehicle after it has been damaged, describing what may legally be done with it.
Does a write-off category change a car's insurance group?
No. The group belongs to the model's derivative and is fixed. A Cat N example of a car sits in exactly the same insurance group as an undamaged one — but its market value is lower and insurers often price it differently, so your premium may not be the same.
What do Cat S and Cat N mean?
Cat S means the car suffered structural damage and was uneconomic to repair, though it may legally be repaired and returned to the road. Cat N means the damage was not structural and the write-off was purely economic. They replaced the older Cat C and Cat D in 2017.
Can you insure a Cat S or Cat N car?
Yes. Most insurers will cover a properly repaired Cat S or Cat N vehicle, though some decline Cat S specifically and others ask for engineer's reports or repair documentation. Expect fewer options and a lower agreed value than for an undamaged equivalent — and shop around, because appetite varies a great deal.
Is insurance cheaper on a written-off car?
Sometimes, because the car is worth less and a total-loss payout would be smaller. But the saving is often offset by a restricted choice of insurers and additional underwriting requirements. The bigger financial effect is on resale value, which typically falls 20 to 40% below an undamaged equivalent and stays there permanently.
Do I have to declare that my car is a write-off?
Yes, if you know. It is material information, and an undisclosed category gives an insurer grounds to reduce a claim or void the policy. If the car was written off and repaired before you bought it, the obligation is still yours — which is why a provenance check before purchase matters.
How can I tell if a car has been written off?
The write-off is recorded on industry databases and surfaces in a paid vehicle history check. The free DVLA vehicle enquiry service does not show write-off categories, so a history check is worth the small cost on any used purchase. Signs to watch for in person: mismatched panel gaps, overspray and a suspiciously low price for the mileage.
Should I buy a Cat N or Cat S car?
Cat N can be sensible value if the damage was genuinely cosmetic and the repair is documented. Cat S deserves far more caution, because structural repair quality determines whether the car protects you in another accident. In both cases get an independent inspection, see the repair evidence, and confirm you can insure it at an acceptable price before buying.
Other cases where the group isn't the whole story
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Check my insurance group →Sources & further reading
- Thatcham Research — The motor insurers' automotive research centre. Co-runs the Group Rating Panel that sets UK insurance groups, and publishes the Vehicle Risk Rating (VRR) framework.
- Association of British Insurers (ABI) — The trade body for UK insurers. Co-runs the Group Rating Panel behind the 1–50 insurance group scale.
- DVLA — Get vehicle information — The official GOV.UK service for vehicle details by registration. Our checker uses the DVLA's Vehicle Enquiry Service API, the same underlying record.