Cat S and Cat N Meaning: Write-Off Categories Explained

Last updated 24 September 2026.

Cat S and Cat N cars turn up at every auction and in plenty of part exchanges, and they can look like good buying. They can also cost you money, or land you in trouble, if you do not know what the category means or forget to tell your customer. This guide explains the write-off categories A, B, S and N, the difference between Cat S and Cat N, what happened to the old Cat C and D, and what you need to check and disclose as a dealer when you buy and sell them.

This is general guidance based on GOV.UK, the Association of British Insurers (ABI) Code of Practice and UK consumer law as of September 2026, not legal advice. Check anything you are unsure about with the relevant body or a solicitor.

Cat S and Cat N meaning in brief

Cat S (structural): written off after damage to the car's structural frame or chassis. It can be repaired and used on the road again.
Cat N (non-structural): written off after damage that did not affect the structure. It can be repaired and used on the road again.
Cat A and Cat B can never go back on the road. Cat A is crushed whole. Cat B's body shell is crushed but some parts can be reused.
Cat C and Cat D are the old repairable categories, replaced by S and N on 1 October 2017.

What is an insurance write-off?

When a car is damaged and the owner claims, the insurer decides whether to repair it or write it off. If the car is written off, the insurer pays the owner the car’s current value instead of paying for repairs (GOV.UK: insurance write-offs).

Every written-off car is then put into one of four categories. Insurers categorise cars using the ABI’s Code of Practice for the Categorisation of Motorised Vehicle Salvage, the current version of which was published on 28 May 2025. The Code says the category must be decided by an “appropriately qualified person”, an assessor who holds a current salvage categorisation qualification. The insurer then records the car on the Motor Insurance Anti-Fraud and Theft Register (MIAFTR), the insurance industry’s write-off register, which is also how DVLA is told.

The write-off categories: A, B, S and N

Category	What it means	Can it go back on the road?
A (scrap)	Cannot be repaired. The entire vehicle has to be crushed.	No
B (break)	Cannot be repaired. The body shell has to be crushed, but other parts can be salvaged.	No
S (repairable structural)	Can be repaired following structural damage.	Yes, once repaired to a roadworthy condition
N (repairable non-structural)	Can be repaired following non-structural damage.	Yes, once repaired to a roadworthy condition

Source: GOV.UK: insurance write-offs. You will sometimes see these shortened to “Cat A, B, S and N”. Our guide to motor trade jargon covers the rest of the shorthand you will hear at auction.

What counts as structural damage?

The ABI Code of Practice treats damage as structural (Cat S) if any structural part of the car needs repairing, realigning to its original dimensions or replacing. It lists examples such as the chassis legs, the front bulkhead, the inner sills, the reinforcements inside the A and B pillars, the inner wings and wheel housings, and the large one-piece castings used in some newer cars. Cosmetic repairs that do not involve realigning the structure do not count.

Non-structural damage (Cat N) covers parts such as the bumpers, bonnet, front wings, door skins, roof panel, boot lid or tailgate. The Code notes that even when damage is non-structural, there may still be safety-critical items that need replacing.

The Code also covers electric and hybrid cars: if a high-voltage battery forms part of the car’s structure and is damaged, that is structural damage.

Cat S vs Cat N: what is the difference?

	Cat S	Cat N
Type of damage	Structural frame or chassis	Not structural
Can it be used again?	Yes, once roadworthy	Yes, once roadworthy
Log book (V5C)	Reissued with a note of the category	Reissued with no note of the category
Recorded on the insurance write-off register	Yes	Yes
Must you disclose it when you sell?	Yes	Yes

The type of damage is what matters, not how much it cost to fix. A Cat N car with heavy cosmetic damage might have needed more work than a Cat S car with a small structural repair. Judge each car on its own damage and the quality of the repair, not just the letter.

Can Cat S and Cat N cars go back on the road?

Yes. GOV.UK says you can use a Cat S or Cat N vehicle again once it has been repaired to a roadworthy condition. It does not have to be registered from scratch: the owner keeps the log book or gets a reissued one, as explained below.

Category A and B cars cannot come back. GOV.UK says a UK vehicle that is a Category A or B write-off counts as “seriously damaged” and cannot be registered with DVLA (GOV.UK: vehicle registration). The ABI Code says the MIAFTR entry for these cars must make sure the V5C is never reissued.

What happens to the V5C log book?

When an owner keeps a written-off car, the insurer pays out and sells the car back to them. According to GOV.UK:

To keep a Cat S car, the owner sends the complete log book to the insurer and applies for a free duplicate using form V62. DVLA records the vehicle’s category in the new log book.
To keep a Cat N car, the owner can keep their existing log book.

The ABI Code’s flowchart matches this: a Cat S car’s V5C is reissued “with a literal comment depicting vehicle status”, while a Cat N car’s V5C is reissued with no comment added.

That has a practical consequence for you: you cannot rely on the V5C to spot a Cat N car. A history check is the only reliable way to find out.

Insurance and finance

Insurance. Insurers set their own rules on write-offs. Some will not cover a Cat S or Cat N car at all, and others may want evidence that the car has been properly repaired. If you are buying one for yourself, get a quote before you commit. When you apply, answer the insurer’s questions honestly: under the Consumer Insurance (Disclosure and Representations) Act 2012, you have a duty to take reasonable care not to make a misrepresentation to your insurer. Getting it wrong could mean a claim is refused or reduced.

As a dealer, tell customers to check insurance before they buy. A buyer who cannot insure the car they have just bought is an unhappy buyer.

Finance. Lenders set their own criteria too, and some will not fund a written-off car. Check your finance panel’s rules before you advertise a Cat S or Cat N car with finance examples, so you do not take a deposit on a deal that cannot be funded.

How being Cat S or Cat N affects value

A Cat S or Cat N car is usually worth less than the same car with no write-off record, and that follows it every time it is sold. How much less depends on the car, the damage, the quality of the repair and how much paperwork comes with it, so there is no fixed discount. Price it against comparable write-off stock, not clean cars, and remember the next buyer’s reduced insurance and finance options will limit who can buy it.

The lower price is also why these cars attract buyers. That makes honest disclosure even more important: a customer who knew and chose a Cat N car for the price is a very different customer from one who finds out later.

Buying Cat S and Cat N cars as a dealer

Whether it comes from auction, a trade seller or a part exchange, check a write-off car more carefully than a clean one:

Run a history check before you buy. A write-off and salvage check shows whether the car is recorded as written off and in which category. Haswent’s MotorCheck integration runs MotorCheck reports, including write-off, finance and stolen checks, from inside the system. Our MotorCheck trade history check announcement has more on how it works.
Compare the V5C. For a Cat S car, the log book should show the category. If a history check says Cat S and the V5C says nothing, find out why.
Ask for the repair evidence. Invoices, photos taken before and during the repair, parts lists and the name of the bodyshop. Ask whether the repair followed the manufacturer’s repair methods.
Check the safety systems. The ABI Code says airbags, seat belts and seat belt pre-tensioners from salvage must never be re-used. Check that any that deployed were replaced, and that there are no airbag or other warning lights on the dash.
Get an independent inspection for Cat S cars, including alignment and geometry, from someone qualified to assess structural repairs. Our free vehicle inspection checklist covers the rest of the car.
Check the mileage and MOT history. Compare the mileage with the MOT history and look for gaps around the date of the write-off.
Record everything against the car, so whoever sells it can show the customer what was checked.

If your business is wholly or mainly buying written-off vehicles and repairing and reselling them, you count as a motor salvage operator under section 21 of the Scrap Metal Dealers Act 2013 and need a scrap metal dealer licence from your council.

Selling Cat S and Cat N cars: what you must tell buyers

Selling a repaired Cat S or Cat N car is legal. Hiding that it is one is not.

Unfair trading. Under the Digital Markets, Competition and Consumers Act 2024 (DMCC Act), leaving out information the average consumer needs to make an informed decision is a misleading omission, and so is giving that information in a way that is unclear or too late. Trading Standards guidance for car dealers gives “failing to inform a consumer that a car has previously been an insurance write-off” as a specific example (Business Companion: selling used vehicles).

Consumer Rights Act 2015. A car you sell must be of satisfactory quality and as described. If you describe a Cat S car as having “no accident damage”, or leave out the category and the buyer later finds it, you risk a claim for a refund, repair or price reduction.

Our guide to the legal requirements for running a used car dealership covers both laws in more detail.

In practice:

Say it in the advert. Put the category in the description on your website, AutoTrader and anywhere else you advertise, not just on the forecourt. Do not describe the car as “HPI clear” or “no accidents”.
Say it before they commit. Tell buyers before they pay a deposit or sign, including on phone, video and online sales, not at handover.
Get it in writing. Put the category on the order form and invoice, and ask the buyer to sign to confirm they were told.
Show your checks. Offer the history check and repair evidence. It builds trust and shows you disclosed properly.

What happened to Cat C and Cat D?

Before 1 October 2017, the repairable write-off categories were C and D. That is when a new version of the ABI’s salvage Code of Practice came into effect and replaced them with S and N (AA: car damage categories). GOV.UK described the old categories like this (GOV.UK insurance write-offs page, archived September 2018):

Category C: could be repaired, but it would cost more than the vehicle’s worth.
Category D: could be repaired and would cost less than the vehicle’s worth, but other costs (such as transporting the vehicle) took it over the vehicle’s value.

You will often hear that Cat C became Cat S and Cat D became Cat N. That is a rough guide only. C and D were about cost, while S and N are about the type of damage. A Cat C car could have had only cosmetic damage if it was worth very little, and a Cat D car could have had structural damage. Cars written off before October 2017 still show as Cat C or Cat D in history checks. Disclose them to buyers in exactly the same way.

How Haswent helps

Haswent’s stock management keeps each car’s history in one place. Add a car by its registration and the details are filled in, then view its MOT history, run MotorCheck reports and record its condition and costs. When you sell a Cat S or Cat N car, the checks you made are on record with the car.

Sources

Frequently asked questions

What does Category S mean on a car?

Category S (Cat S) means an insurer has written the car off after structural damage, such as damage to the chassis or structural frame, but it can be repaired. GOV.UK says a Cat S vehicle can be used again once it has been repaired to a roadworthy condition, and DVLA records the category in the log book (V5C).

What does Cat N mean?

Category N (Cat N) means an insurer has written the car off after non-structural damage, such as to bumpers, wings, doors or the bonnet. It can be repaired and used again once it is roadworthy. The ABI Code of Practice notes that a Cat N car may still have had safety-critical parts that needed replacing.

What is the difference between Cat S and Cat N?

Both are repairable write-offs. Cat S cars had damage to the structural frame or chassis. Cat N cars had damage that did not affect the structure. Under the ABI Code of Practice, a Cat S car's reissued log book carries a note of its category, while a Cat N car's does not, although both are recorded on the insurance industry's write-off register, so a write-off history check will pick up either.

Can a Cat S or Cat N car go back on the road?

Yes, once it has been repaired to a roadworthy condition. Category A and B cars cannot: GOV.UK says a UK vehicle that is a Category A or B write-off counts as seriously damaged and cannot be registered with DVLA.

What happened to Category C and D write-offs?

They were replaced by Categories S and N when a new ABI Code of Practice came into effect on 1 October 2017. Cat C and D were based on the cost of repair compared with the car's value, while S and N describe the type of damage, so they do not map exactly. Cars categorised before the change still show as Cat C or D.

Do I have to tell my insurer a car is Cat S or Cat N?

If your insurer asks, yes. Under the Consumer Insurance (Disclosure and Representations) Act 2012 you must take reasonable care not to make a misrepresentation to your insurer, and insurers commonly ask whether a car has been written off. Some insurers will not cover write-offs, so check before you buy.

Do dealers have to tell buyers a car is a Cat S or Cat N?

Yes. Trading Standards guidance gives failing to tell a consumer that a car has previously been an insurance write-off as an example of a misleading omission, which is an unfair commercial practice under the Digital Markets, Competition and Consumers Act 2024. Tell buyers clearly in the advert and before they commit, and get them to sign to confirm.

Cat S and Cat N Meaning: Car Write-Off Categories Explained