What Do Cat S, N, A & B Mean? UK Write-Off Categories Explained
If an insurer has ever declared a car a total loss, it gets assigned a salvage category — and that letter tells you a lot about what happened to it, and whether it can legally be on the road at all.
When a car is damaged badly enough that an insurer decides repairing it costs more than it's worth (or it's simply too dangerous to repair), the insurer writes it off and assigns it one of four salvage categories. Since October 2017, the UK has used a system set out by the ABI (Association of British Insurers) — Cat A, Cat B, Cat S and Cat N — which replaced the older Cat A, Cat B, Cat C and Cat D system. The category is recorded on the industry's total-loss register and stays attached to that vehicle for the rest of its life, even after a change of keeper or number plate.
Category A
Scrap only
The worst damage class. The whole vehicle must be crushed — no parts may be reused, even for spares.
Can never return to the road as a carCategory B
Break for spares
The body shell must be destroyed and can never return to the road, but individual parts can be salvaged and resold.
Can never return to the road as a carCategory S
Structural damage
The vehicle had damage to its structural frame or chassis. It can legally return to the road once professionally repaired and re-registered.
Can legally return to the roadCategory N
Non-structural damage
Damage was cosmetic, electrical or otherwise non-structural, but the insurer judged repair uneconomical. Can legally return to the road once repaired.
Can legally return to the roadCat C and Cat D — the old system
If you're looking at an older vehicle, its write-off record might predate the October 2017 change and show a legacy Cat C or Cat D instead. Cat C meant the repair cost was close to or exceeded the car's value; Cat D meant the salvage value made repair uneconomical, often for comparatively minor damage. They broadly map onto today's Cat S and Cat N, but not on a strict one-to-one basis — the categorisation criteria genuinely changed in 2017, not just the letters.
Does a write-off category mean the car is dangerous?
Not automatically. A Cat S or Cat N car that's been properly repaired by a competent body shop and passes an MOT can be entirely safe to drive — plenty of perfectly good cars carry one of these markers after a claim that had nothing to do with the buyer's ownership. The risk is a repair that wasn't done properly, particularly on the structural (Cat S) side. That's precisely why knowing the category, the loss date and which insurer reported it matters: it turns a guess into a question you can actually investigate — ask for repair invoices, get an independent structural inspection, and price the car accordingly. A write-off history should never be hidden from a buyer, and it should never be ignored either.
A write-off check relies on insurers reporting total losses to the industry register. A result of “no write-off record found” means no insurer has reported this vehicle as a total loss on that register — it isn't an absolute guarantee no accident ever happened, which is true of any provenance check, from any provider, anywhere.
Frequently asked questions
What does Category S mean on a car?
Category S ("structural") means the vehicle sustained damage to a structural part of the frame or chassis and was declared a total loss by an insurer, but it has since been professionally repaired to a safe, roadworthy standard and can legally be driven again. It's still worth significantly less than an equivalent car with no write-off history, and it's worth asking for the repair paperwork.
What does Category N mean?
Category N ("non-structural") means the damage did not affect the vehicle's structural frame — think bodywork, electrics, wheels or interior — but the cost of repair was judged uneconomical relative to the car's value by the insurer. Like Cat S, a Cat N car can legally return to the road once repaired.
What's the difference between Cat A and Cat B write-offs?
Both are the more severe categories and neither vehicle may ever be put back on the road as a complete car. Cat A means the entire vehicle must be crushed with nothing salvaged. Cat B means the body shell must be destroyed, but individual parts (engine, gearbox, panels) can legally be removed and sold on.
Are Cat C and Cat D still used?
Cat C and Cat D were the UK's write-off categories before October 2017, when the ABI (Association of British Insurers) replaced them with the current S/N system. You may still see Cat C or Cat D on the history of an older vehicle written off before the change — they broadly correspond to today's S and N categories, though the mapping isn't exact.
Does a write-off category mean the car is unsafe to drive?
Not necessarily — a Cat S or Cat N vehicle that has been properly repaired and passes an MOT can be perfectly safe. The risk is a repair that wasn't done to a proper standard, which is exactly why the write-off category and insurer-reported details matter: they tell you what happened so you (or an independent inspector) can judge the repair on its merits, rather than buying blind.
How can I check if a specific car has a write-off record?
Enter the registration number into MotorFile's free check for basic DVLA and MOT data. The Full Vehicle Check (£9.99) additionally queries the insurance industry's total-loss register and reports the write-off marker, category, loss date and reporting insurer where a record exists — or tells you honestly that no check has been run, rather than guessing.
Check a specific vehicle's write-off record
The £9.99 Full Vehicle Check queries the insurance industry's total-loss register for write-off category, loss date and reporting insurer, alongside a stolen-marker and outstanding-finance check.
See what's included