What are car insurance write-off categories (Cat A, B, S & N)?
In the UK, car insurance write-off categories are used to classify vehicles that are too damaged to repair safely or economically.
These labels—Cat A, B, S and N—aren’t just administrative codes. They tell a story about the car’s past, its roadworthiness, and how it should be handled going forward.
You’ll see them pop up in insurance documents, auction listings, second-hand ads—even in DVLA records. But many drivers still don’t understand what these categories actually mean. Is a Category N car safe to drive? Can you insure a Cat S? What makes a car a total loss in the first place?
This guide walks you through everything you need to know. We’ll start by explaining what it means when a car is “written off,” then break down each category—what it covers, what it doesn’t, and how it affects resale, repairs, and your rights as a driver or buyer.
If you’ve had a car written off, are considering buying one that has been, or just want to understand the process before it happens to you—this is where you start.
What does it mean when a car is written off?
A car is written off when your insurer decides it’s no longer financially viable or safe to repair, usually after a collision or serious damage.
This means they’ll declare it a total loss and either scrap it or assign it a write-off category.
The decision is largely financial—but not always. Insurers calculate the cost to repair your car, including parts, labour, VAT, and downtime. If that cost exceeds a certain percentage of the car’s current market value—often around 50% to 60%, depending on the insurer—it’s labelled a write-off. But safety plays a part too. Even if the repairs are affordable, the vehicle might still be structurally unsound, or its roadworthiness can’t be guaranteed.
Once declared a total loss, the vehicle is assigned a write-off category by the insurer. These categories help everyone involved—buyers, sellers, insurers, DVLA—understand what level of damage occurred, and what happens next.
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Get QuotesWhy do insurers categorise write-offs?
Insurers use write-off categories to clearly communicate the extent of damage to a vehicle, helping protect buyers, support road safety, and prevent fraud.
The system ensures damaged cars are treated consistently—whether they’re being repaired, scrapped, or sold.
When a car is written off, that’s just the beginning. What happens next—can it go back on the road, be stripped for parts, or must it be crushed—depends on the damage. Categorisation gives insurers, DVLA, mechanics, and even future buyers a common language to describe that outcome.
It’s also about transparency. When you buy a used car, you need to know if it was ever written off, and if so, how serious the damage was. A Category N car with minor cosmetic issues is very different from a Category S vehicle with structural repairs. The categories make that distinction visible, on paper and in history checks.
From a legal and ethical standpoint, the system helps stop unsafe cars slipping through the net. A vehicle that’s been heavily damaged but improperly repaired could be dangerous on the road. Categories—and the processes behind them—exist to prevent that risk from being passed down to the next owner.
How have write-off categories evolved over time?
The UK updated its car insurance write-off categories in October 2017, replacing the older Category C and D system with Category S and N.
This change was made to shift focus from repair costs to vehicle safety.
Previously, write-offs were primarily classified based on whether the cost of repairs exceeded the vehicle’s value. While that worked in theory, it didn’t always reflect the true condition of a car. A vehicle could be repaired cheaply but still be structurally compromised—yet still end up as a Category D, leaving buyers unaware of the risks.
To fix this, the Association of British Insurers (ABI) revised the system. The current categories—S for structural damage, N for non-structural—are clearer, safety-led, and easier to interpret. Categories A and B remained unchanged, reserved for vehicles too damaged to return to the road.
The new framework helps buyers make more informed decisions, especially in private sales and auctions. It also standardises reporting, giving insurers and the DVLA a more accurate way to record a car’s post-accident condition.
If you’re buying a used vehicle post-2017, any write-off classification should be based on this updated system.
What is a Category A write-off?
A Category A write-off is a vehicle so badly damaged it must be completely scrapped, with no parts reused and nothing salvaged—not even for spares.
It’s the most severe classification an insurer can assign.
Cat A vehicles are usually total losses from catastrophic damage—serious road collisions, intense fires, or flooding that leaves nothing recoverable. Even the smallest components are considered unsafe or too damaged to risk reusing.
You’ll rarely encounter these vehicles unless you work in salvage or insurance. They don’t appear on forecourts, auction sites, or private listings. But their existence in the classification system serves a clear purpose: to close the loop on vehicles that are truly beyond saving, and ensure they’re removed from circulation entirely.
If your car is declared Category A, there are no options to repair or recover it—it’s the end of the road.
What is a Category B write-off?
A Category B write-off is a vehicle that’s too damaged to ever return to the road, but some of its parts may be salvaged and reused.
The shell or chassis, however, must be crushed—by law.
This classification usually follows major structural damage from collisions, fires, or floods. While the core body is unsafe or compromised, certain components—like the engine, gearbox, wheels, or interior trim—might still be intact. These parts can legally be removed by a licensed breaker and sold on, but the vehicle itself can never be driven again.
That’s an important distinction. You’ll sometimes see “Cat B breaker” listings at salvage auctions, which means the car is being sold purely for parts. These vehicles are registered with the DVLA as destroyed, and cannot be re-registered or issued a logbook.
A vehicle is rear-ended at high speed, bending the frame and crumpling the roof—but the engine and wheels are untouched. The insurer categorises it as Cat B. The shell is crushed, but the working parts are stripped and sold.
If you’re not in the motor trade, you won’t deal with Cat B cars directly—but it’s worth understanding the category, especially when buying used parts.
What is a Category S write-off?
A Category S write-off is a vehicle with structural damage that can be repaired and returned to the road, but only after it’s been properly fixed and re-registered.
The “S” stands for Structural.
This classification replaced the older Category C in 2017. It applies when a car’s frame, chassis, or crumple zones have been compromised in a collision or similar incident—but the vehicle isn’t beyond repair. The damage might include things like bent suspension components, twisted sills, or a collapsed boot floor.
Cat S vehicles can legally go back on the road, but only once repairs have been completed and the DVLA is notified. The insurer must inform the DVLA of the write-off, and the car’s V5C logbook becomes void until reissued. If a seller offers a Cat S car without a current V5C, it’s a red flag.
What makes Cat S risky?
Poor structural repairs can affect a car’s crash safety in the future—even if the vehicle looks fine on the surface. That’s why buying a Cat S car demands caution, proof of repairs, and ideally, an independent inspection.
Cat S write-offs often sell at a discount—but buyers need to be aware of the responsibilities and risks that come with them.
What is a Category N write-off?
A Category N write-off is a vehicle with non-structural damage—such as cosmetic, electrical, or mechanical faults—that the insurer decided not to repair.
These cars are usually safe to drive once fixed and don’t require re-registration with the DVLA.
The “N” stands for Non-Structural. Unlike Category S, these vehicles haven’t suffered damage to the core body or chassis. Instead, insurers might write them off due to faulty airbags, damaged electrics, cosmetic panel dents, or mechanical problems that are expensive to put right.
Because the frame isn’t compromised, Cat N cars don’t need a new V5C document. Once repaired, they can go back on the road without any extra paperwork—but the write-off status will remain on the vehicle’s history forever, which affects resale value and insurance.
A car has a failed ECU, minor front-end scuffs, and damaged parking sensors. The repair cost is £3,000—close to its value. The insurer writes it off as Cat N. A buyer later fixes it for less using second-hand parts and puts it back on the road.
Cat N vehicles often appeal to bargain hunters, but as with any write-off, buyers should insist on repair documentation and carry out a vehicle history check.
Do write-off categories affect vehicle value and insurance?
Yes—being classified as a write-off significantly reduces a vehicle’s resale value and can lead to higher insurance premiums.
Even if a car has been professionally repaired, the stigma of its write-off status follows it for life. If you’re looking to insure a previously written-off vehicle or simply want to compare prices, you can get a car insurance quote in minutes through SimplyQuote.
For buyers, this often means paying 20% to 40% less than the market rate for an equivalent “clean” vehicle. But that discount reflects risk and reputation. Insurers may be wary about the quality of repairs, especially with Cat S cars where structural damage was involved. Some car insurance companies won’t offer comprehensive cover on a previously written-off vehicle, or they’ll apply a higher excess.
Impact snapshot:
| Write-Off Type | Typical Value Impact | Insurance Reaction |
|---|---|---|
| Cat N | -20% to -30% | Higher premium possible |
| Cat S | -25% to -40% | May limit cover or load price |
| Cat B / A | Not roadworthy | Cannot be insured |
It’s not just about the insurer, either. Some buyers avoid written-off vehicles entirely, especially if repair history is unclear. That narrows the resale market. Others may undervalue your car in part-exchange deals simply because of the write-off flag in the HPI check.
If you own a written-off vehicle or plan to buy one, expect long-term consequences—even if it runs perfectly.
How can you check a vehicle’s write-off status?
You can check if a vehicle has been written off by running a vehicle history check with a service like HPI Check, AutoTrader, or the DVLA.
These reports reveal if a car was categorised as Cat A, B, S, or N—and when.
This step is essential when buying a used car privately or from an unfamiliar dealer. Some write-offs look pristine on the surface, and not all sellers disclose the history. A proper check ensures you’re not buying a structurally compromised or previously written-off vehicle without knowing it.
Common tools include:
- HPI Check: Industry standard, full category detail
- AutoTrader Vehicle Check: Highlights write-off status and finance flags
- DVLA V5C Check: Free, but limited—it won’t show Cat N/S classifications
- MyCarCheck, TotalCarCheck: Budget-friendly options with basic damage history
Paid reports usually cost between £10 and £20, and are well worth it for peace of mind. They’ll often include details like the category assigned, date of write-off, and whether the car has been scrapped, repaired, or retained.
Without this check, you risk overpaying for a car that’s worth far less—or worse, buying something unsafe to drive.
Should you buy a written-off vehicle?
Buying a written-off vehicle can save you money, but it comes with risks around safety, insurance, and resale value—especially if repairs weren’t properly documented.
For some buyers, it’s a smart move. For others, it’s a gamble not worth taking.
The main attraction? Price. Cat N and Cat S vehicles often sell for 20% to 40% less than their undamaged equivalents. If you’re handy with repairs—or trust the source—it can be a cost-effective way to get more car for your money. Just be prepared for reduced resale value and possibly higher insurance premiums.
You find a 2019 VW Golf listed £3,500 below market value. It’s a Cat S with full repair invoices and a clean MOT. You save money upfront, but later discover your insurer won’t offer comprehensive cover—and resale interest is limited.
Buy a written-off vehicle only if:
- You’ve seen evidence of professional repairs
- You’ve done a full HPI or vehicle history check
- You’re not relying on resale value later
- You’re comfortable with the insurance implications
For buyers who understand the risks and do their homework, a written-off vehicle can be a legitimate bargain. For others, it’s often safer to walk away.
What steps should you take if your car is written off?
If your car is written off, you’ll need to accept or dispute the insurer’s valuation, inform the DVLA, and decide whether to let the insurer keep the vehicle or buy it back yourself.
Here’s how to handle it, step by step:
- Wait for the insurer’s offer.
They’ll assess the damage and provide a settlement based on your car’s pre-accident market value. If you disagree with the figure, you can push back with proof—recent adverts, mileage records, or maintenance history. - Decide what to do with the car.
If it’s Cat A or B, it must be scrapped. If it’s Cat S or N, you may have the option to buy it back. In that case, the payout is reduced by the car’s salvage value. - Notify the DVLA.
Complete Section 9 of the V5C logbook (or use the DVLA’s online service) to report the vehicle as written off. If you sell the car to your insurer, you must send them the V5C. - Remove your insurance and tax.
Cancel your insurance and claim back any unused portion of your car tax via GOV.UK. - Keep records.
Save all communication and documents in case you need them later—for insurance disputes or if buying back the vehicle.
Getting your car written off can feel abrupt, but with the right steps, you stay in control of the outcome—and your next move.
Why do some insurers write off repairable cars?
Insurers sometimes write off repairable cars because the cost of parts, labour, or delays outweighs the car’s market value—even if the damage looks minor.
In many cases, it’s a financial decision, not a mechanical one.
It’s easy to assume a write-off means catastrophic damage. But the economics of vehicle repair can be surprisingly unforgiving. A car worth £4,000 might be written off for £2,500 worth of repairs—if that includes genuine parts, specialist labour, and VAT. It’s not about what’s possible—it’s about what’s viable for the insurer.
This is especially common with older vehicles, low-value cars, or those needing parts in short supply. It’s also more frequent with modern cars packed with sensors, airbags, and ADAS systems—where even a minor bump can trigger costly diagnostics and recalibration.
A five-year-old Nissan Qashqai has a crumpled bumper and damaged parking sensors. No frame damage, no injuries. But the repair quote—using genuine parts—hits £3,100. The car is valued at £4,200. The insurer writes it off.
In cases like these, the vehicle may still be safe to drive once repaired. But the insurer makes the numbers-based call, and the write-off label is applied regardless.
Final thoughts
Car insurance write-off categories aren’t just technical labels—they’re signals. They tell you what happened, what was decided, and what you need to consider before making your next move.
Whether you’re dealing with a claim or browsing used cars, knowing the difference between Cat A and Cat N can help you avoid costly mistakes. Not all write-offs are unsafe. Not all bargains are wise. And not every insurer decision is final if you know what questions to ask.
If you’re ever unsure, ask to see repair records. Run a vehicle check. Look up the category. This isn’t about being suspicious—it’s about being informed. And in a market where write-offs are increasingly common, that knowledge is power.
Now you know what the categories mean. What they really mean.
And that makes you better prepared—whether you’re on the phone with your insurer or eyeing up that tempting deal on a second-hand car.
Frequently Asked Questions (FAQs)
Yes. Once repaired, a Cat N car can be legally driven and doesn’t require re-registration. But insurers will still see it as a write-off.
No. The V5C logbook won’t show the write-off category. You’ll need to run a vehicle history check to see that information.
No. Once a vehicle is officially recorded as written off, the category stays on its history permanently.
Often, yes. Some insurers may increase your premium or offer reduced cover depending on the category and repair evidence.
Most insurers settle within 7–14 days of agreement, but delays can occur if there’s a dispute over value or paperwork.
Yes. You’ll receive a refund for any full months remaining once the DVLA is notified that your car is no longer in use.
Yes—failing to disclose a write-off is considered misrepresentation and could invalidate the sale or lead to legal action.
It depends on the quality of repairs. Always request documentation and consider a professional inspection before buying.