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Cat S and Cat N cars: what they mean and how to check

Updated 1 Nov 2026

Cat S and Cat N are insurance write-off categories. Cat S means the car was written off with damage to its structural frame or chassis. Cat N means it was written off with non-structural damage. Both can return to the road once repaired to a roadworthy condition, but MOT history does not show the category. A log book can show Cat S but not Cat N, so use a paid history check that includes write-off details.

What does written off mean?

An insurer writes off a car when it pays the owner the vehicle’s current value instead of paying to repair it. The insurance company decides whether to write it off, and an “appropriately qualified person” decides the category.

Category Repairing it Using it (GOV.UK)
A Cannot be repaired The entire vehicle has to be crushed
B Cannot be repaired The body shell has to be crushed, but other parts can be salvaged
S Can be repaired following structural damage Can be used again if repaired to a roadworthy condition
N Can be repaired following non-structural damage Can be used again if repaired to a roadworthy condition

GOV.UK calls S and N “constructive losses”: the car could be repaired, but the cost would exceed its replacement value.

The categories come from the insurers’ code of practice, published by the Association of British Insurers (latest version 28 May 2025).

Cat S and Cat N in more detail

A Cat S car has damage to part of its structural frame or chassis. Damage is structural if a structural element needs repair, replacement or realignment to its original dimensions.

Examples of structural parts in the code include the front chassis legs, front bulkhead, inner pillar and sill reinforcements, roof side rails, rear inner wings and welded chassis frames.

A Cat N car has not sustained damage to its structural frame or chassis. Examples of non-structural parts include bumpers, the bonnet, front wings, doors, rear quarter panels, the roof panel, boot floor and boot lid or tailgate.

The code says a Cat N car may still need safety-critical parts replaced. For electric cars, damage to a battery that forms part of the structure means Cat S.

Categories S and N came in with the code that took effect in October 2017. HPI’s sample report lists Cat C and Cat D among its categories for cars written off since January 1997, and says S and N should over time replace C and D. It says S and N describe the type of damage rather than the cost of repair.

How to find out if a car has been written off

Citizens Advice says a private history check will tell you if a car has been written off, repaired and returned to the road, and if it is reported stolen or has money owing on it. It costs up to £20 (checked 1 Nov 2026).

HPI’s full check lists insurance write-off information and costs £19.99. HPI’s Basic Check costs £9.99 but leaves out write-off details (both checked 1 Nov 2026). You can compare the information listed by different reports.

Can the category be removed?

The insurers’ code says that, other than to correct errors, register data “should not be modified or removed”, and that re-categorisation may only happen in exceptional circumstances. So repairing a car does not remove its category, and a history check can still show it to a future buyer when you sell.

Insurance, finance and value

Get an insurance quote before buying. GOV.UK’s consumer guide says insurance can be more expensive and not every insurer will automatically provide cover for a previously written-off vehicle. A quote lets you check whether any saving on the purchase price could be offset by a higher premium.

GOV.UK says Cat S vehicles are often slightly cheaper than similar age and mileage vehicles, and that a written-off car returned to a good condition often represents good value. It also says to beware if the price looks too good to be true.

If you plan to use finance, ask the lender before you commit.

Checklist for buying a Cat S or Cat N car

  1. Run our free MOT check. It shows the official MOT history and flags a mileage reading lower than an earlier one, a dangerous defect in the last 3 years and a last MOT that was a fail. Ask the seller about anything flagged, and about long gaps between tests.

  2. Ask the seller in writing whether the car has been written off, and in which category.

  3. Get a history check that includes write-off details. Not every package does. Use our report comparison page to see what each report lists.

  4. See the V5C log book and check the VIN. Make sure the VIN agrees across the vehicle and matches the log book. Check the V5C details against DVLA records. Citizens Advice says never to buy a car without the log book.

  5. Ask who handled the car between the write-off and the repair. Check that it has been properly repaired and is roadworthy.

  6. Consider an independent inspection. GOV.UK suggests an independent expert or engineer who can identify structural damage. Citizens Advice says an independent report costs around £120 to £250 (checked 1 Nov 2026).

  7. Get an insurance quote before agreeing to buy.

  8. Check the service history and recalls. Ask for the full service history, and check whether the car has a safety recall.

  9. After you buy, tell your insurer that the car was previously declared a total loss. GOV.UK says an insurer can reject a claim on the grounds of non-disclosure if you don’t.

If you find out after buying

Keep the advert, the receipt and your messages with the seller. Citizens Advice (advice for England) says that if something is wrong with a used car, including if it doesn’t match the advert or description, you might have a legal right to a repair, the cost of a repair, or some or all of your money back.

It also says you won’t be entitled to anything if you were told about the problem when you bought the car and it was fully explained, or if you inspected the car and should have spotted it.

Sources

See a car's MOT history

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