What is a Cat A, B S or N car?
You may have seen several used cars advertised with these categorised labels marked against them, so what do they mean?
The Cazoo editorial team
Published on 20 October 2025 | 1 min read
Buying a second-hand car can be an expensive and stressful process, especially if you have a tight budget.
If you are regularly looking to find your next used vehicle, you may have stumbled across plenty of cars for sale that say ‘Cat S’ and ‘Cat N’?
You might be thinking, what does this mean? Is it better or worse? Is the car dangerous?
It actually means that the vehicle has previously been involved in an accident and has been written-off by the insurance company, then repaired and has been put back on the road.
So, if you’re looking at a previous written-off car, don’t despair, as we’ve compiled a simple guide to everything you need to know about categorised vehicles.
Why do cars get written off?
Cars can be written-off for all kinds of reasons, but it’s mainly down to the cost of the repair if the vehicle is involved in an accident.
Many insurance companies will work to guidelines, and so, if you’re unfortunate to be involved in an accident, your insurance company will have someone access the damage, then find a reputable garage to repair the car and then tally up the costs.
An insurance company will write off a car if the cost of repairs exceeds the car’s pre-accident value. Because it runs off supplying genuine parts, labour costs, and choosing high-end repair workshops, costs can soon escalate, which causes many cars to be written off for very small bumps and scrapes.
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What is a Category A car?
Let’s start at the top, with a Category A write-off. A car that has been classed as a ‘Cat A’ has been involved in a severe accident, to the extent that it physically cannot ever go back on the road and should be scrapped.
These include vehicles that have been involved in fires, flood damage, and crashes, where the vehicle’s chassis and body shell have been severely distorted, making it extremely dangerous to put back on the road.
You will never see a ‘Category A’ vehicle advertised on the second-hand market, as it’s illegal to repair a car that has been classed as a Cat A, and needs to be destroyed.
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What is a Category B car?
A 'Category B' car will have also been involved in a serious accident, but most of the parts can be salvaged and sold on to make use for other cars of that type on the road.
However, the vehicle’s body shell still must be crushed, as it would have been severely damaged from an impact such as a head-on collision, a rollover or further fire damage.
Just like with Category A vehicles, it’s illegal to repair a car once it’s been declared a Category B write-off and cannot go back on the road.
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What is a Category S car?
You might have seen several used vehicles on the second-hand market that have a ‘Category S’ marker, though.
A Category S vehicle is when a car has been involved in an accident, and has suffered ‘Structural’ damage - hence the name - but can be repaired and put back on the road, if the insurance company thinks it’s safe to do so.
Examples of when a car is classed as a Category S is when the chassis may have been bent, twisted or the crumple zone area has been affected.
A Category S car will need to be repaired by a professional, and will not be allowed back on the road until it’s been safely put back together.
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What is a Category N car?
Another common class of write-off is ‘Category N’, which stands for ‘Non-structural’, which is when a car has suffered minor damage, but still exceeds the vehicle’s pre-accident value to repair.
It could also mean that something within the vehicle will prevent it from being driven, such as brakes or electrical faults. These vehicles are safe to repair and can be put back on the road, as long as they’re done by a professional.
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How do they differentiate between Category C and Category D cars?
If you see a car that is advertised as a ‘Category C’ or ‘Category D’, it is just an older-style of write-off categorisation.
A car that is classed as a ‘Category C’ is a vehicle that has been involved in an accident and has suffered ‘structural’ damage, but is safe to repair. The modern equivalent would be a ‘Category S’.
If a vehicle is a ‘Category D’ write-off, it has suffered minor damage, such as a bumper repair, a paint scratch or a mechanical fault, which still exceeds the pre-accident value of the vehicle. The modern equivalent would be a ‘Category N’.
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What are the benefits?
The biggest upside to categorised vehicles is price, as they will be worth significantly less than a non-categorised example.
This means that they can represent excellent value for money, and if you know what you’re doing, there are some bargains to be had.
For example, a three-year-old Category S Kia Sportage that’s covered 17,000 miles can be yours for just £13,250. In comparison, a non-categorised Sportage of the same age and mileage will set you back £18,350 - a £5,100 difference.
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Should you buy a categorised car?
If you’re thinking about buying a categorised car, we’d suggest that you do your research and make sure you get the car thoroughly inspected before you buy.
Even though the car may have been repaired to a high standard, make sure that it’s safe to use on the road. Take it for a test drive to try and see if it drives in a straight line, if it doesn’t, it could suggest the car’s tracking is out of alignment, or worse, the chassis could be bent.
Category N cars are a safer bet, as they have experienced no structural damage, and could have suffered with something as simple as a damaged bumper. They can also be found on the second-hand market for a lot less than a non-damaged vehicle.
With that in mind, we would suggest if you do decide to buy a categorised vehicle, look for Category N write-offs, as they will still represent excellent value for money, and have limited damage.
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