Quick answer
Cat S means the car had structural damage recorded. This could involve parts of the shell, chassis, crash structure or load-bearing areas. It needs more caution because structural repair quality is very important.
Cat N means the car had non-structural damage recorded. It may sound less serious, but it can still involve expensive repairs such as electrics, suspension, bodywork, airbags, lights, sensors or interior damage.
A Cat S or Cat N car can be worth considering only if the price is right, the repair evidence is strong, the car drives properly, insurance is acceptable and an independent inspection does not reveal hidden problems.
What is the difference between Cat S and Cat N?
The main difference is the type of damage recorded by the insurer. Cat S is structural. Cat N is non-structural. Both categories mean the vehicle was written off by an insurer because repair costs were not considered worthwhile at the time of the claim.
Cat S: structural damage
The car’s structure was damaged. Repair quality, alignment, safety systems and suspension geometry must be checked carefully.
Cat N: non-structural damage
No structural damage was recorded, but the repair can still involve expensive electrical, cosmetic, safety or suspension issues.
What does Cat S mean?
Cat S stands for structural damage. This means the vehicle had damage recorded to structural or load-bearing parts before it was repaired and returned to the road.
- !Structural damage was recorded at some point.
- !Repair quality is extremely important.
- !Panel alignment, suspension geometry and safety repairs should be checked carefully.
- !Cat S cars usually have a stronger resale penalty than Cat N cars.
- !An independent inspection is strongly recommended.
What does Cat N mean?
Cat N means the vehicle was written off without structural damage being recorded. However, that does not mean the damage was small or cheap to fix.
- ✓No structural damage was recorded.
- ✓Damage may still involve bodywork, electrics, suspension, airbags, sensors or safety systems.
- ✓Repair quality still matters.
- ✓Cat N cars are often easier to resell than Cat S cars, but value is still reduced.
- ✓Insurance and resale should still be checked before buying.
Cat S vs Cat N side-by-side
Damage type
Cat S: structural damage. Cat N: non-structural damage.
Risk level
Cat S usually needs more caution, but Cat N can still hide expensive faults.
Repair evidence
Both need invoices, photos, inspection evidence and proof of quality repairs.
Insurance
Both may affect insurance quotes, depending on insurer and vehicle.
Resale value
Both are usually worth less than clear-history cars. Cat S normally suffers more.
Buyer caution
Both need careful checks, but Cat S should almost always be inspected independently.
Should you buy a Cat S or Cat N car?
A Cat S or Cat N car may be worth considering if the price is clearly lower than a similar clear-history car, the repair quality is proven and the paperwork is strong.
Do not buy one just because it looks cheap. A poorly repaired write-off can cost more in the long run and may be harder to insure, sell or trust.
More sensible buy
Good repair evidence, strong MOT history, clean test drive, fair discount and acceptable insurance quote.
Higher-risk buy
No photos, no invoices, seller vague, poor alignment, warning lights, uneven tyre wear or suspiciously cheap price.
What to check before buying
- 1Ask what damage the car originally had.
- 2Ask for repair invoices, photos and inspection evidence.
- 3Check panel gaps, paint match, tyre wear and steering alignment.
- 4Check for dashboard warning lights.
- 5Inspect MOT history for repeated advisories or repairs.
- 6Get insurance quotes before paying a deposit.
- 7Consider an independent inspection before buying.
Use our used car inspection checklist, used car test drive checklist and questions to ask when buying a used car.
Paperwork and history checks
Paperwork matters more on a Cat S or Cat N car than on a normal used car. You need to understand what was damaged, who repaired it and whether the repair was done properly.
Repair invoices
Invoices show what parts and labour were used during repair.
Before repair photos
Photos help you understand the original damage rather than guessing.
MOT history
Repeated advisories can reveal alignment, tyre, suspension or brake issues.
Check MOT history →Service history
A category marker plus no service history makes the car harder to trust.
No service history →HPI/history check
A history check can confirm write-off category, finance and mileage concerns.
Insurance quotes
Check insurance before buying, not after agreeing the deal.
Inspection checklist for Cat S and Cat N cars
Body and paint
Check colour match, overspray, panel gaps, bumper fit, door alignment and uneven reflections.
Structure and underside
Look for bent metal, poor welding, fresh underseal, creases, uneven seams or badly repaired areas.
Suspension and tyres
Check uneven tyre wear, pulling to one side, steering wheel off-centre and suspension noises.
Warning lights
ABS, airbag, engine, traction control or steering lights should not be ignored.
Doors, boot and bonnet
Make sure everything opens, closes and lines up properly without rubbing.
Water leaks
Check carpets, boot floor, headlining and spare wheel well for damp after repair work.
Test drive checks
A test drive can reveal problems that are not obvious while the car is parked. With a Cat S or Cat N car, drive carefully but pay close attention to how the car behaves.
- ✓The car should drive straight without pulling to one side.
- ✓The steering wheel should sit straight on a level road.
- ✓There should be no knocks, clunks or rubbing noises.
- ✓Braking should feel stable without vibration or pulling.
- ✓No warning lights should appear during the drive.
- ✓Air conditioning, parking sensors, cameras and safety systems should work.
Use the full used car test drive checklist before agreeing a price.
How Cat S and Cat N affect value and resale
Lower resale value
Category cars are normally worth less than equivalent clear-history cars.
Harder to sell
Future buyers may be cautious, especially if repair evidence is weak.
Smaller buyer pool
Some buyers avoid write-off category cars completely.
The discount needs to be big enough to cover the extra risk, lower resale value and possible insurance complications. If the price is close to a clear-history car, the category car is usually harder to justify.
Insurance concerns before buying
Do not assume every insurer will treat a Cat S or Cat N car the same way. Some may quote normally, some may ask extra questions, and some may price the risk differently.
- 1Get insurance quotes before buying.
- 2Declare the category marker honestly if asked.
- 3Check whether the insurer needs repair evidence or inspection proof.
- 4Compare comprehensive quotes, not just third-party cover.
- 5Remember future resale may still be affected even if insurance is available.
Cat S and Cat N red flags
- !The seller cannot explain the original damage.
- !There are no repair invoices, photos or inspection records.
- !Panel gaps, paint colour or bumper alignment look wrong.
- !The car pulls to one side or tyres wear unevenly.
- !Airbag, ABS, engine or warning lights stay on.
- !The seller is rushing you or refusing inspection.
- !The price is low but the story does not make sense.
- !The car has fresh paint, fresh underseal or missing trim around repaired areas.
Questions to ask the seller
1. What was the original damage?
Ask for a clear explanation, not vague answers like “minor damage”.
2. Do you have photos before repair?
Before-repair photos help you judge whether the category marker matches the story.
3. Who repaired it?
A proper bodyshop repair is more reassuring than unknown repair work.
4. Are there repair invoices?
Invoices show what was replaced, repaired and inspected.
5. Can I inspect it independently?
A trustworthy seller should not object to a serious buyer arranging inspection.
6. Why is it priced that way?
The price should reflect the category marker, repair evidence and future resale impact.
Common mistakes buyers make
- !Buying a Cat S car without independent inspection.
- !Assuming Cat N always means minor damage.
- !Not checking insurance quotes before paying a deposit.
- !Ignoring missing repair evidence.
- !Paying too close to clear-history market value.
- !Focusing only on bodywork and missing electrical or safety faults.
- !Not checking MOT history for alignment, tyre and suspension clues.
Best mechanic-style advice
With Cat S and Cat N cars, the category is only the start of the story. The real question is what was damaged, how well it was repaired, whether safety systems work correctly and whether the price truly reflects the risk.
A well-repaired Cat N car with strong evidence can sometimes be a sensible buy. A poorly documented Cat S car with bad alignment, warning lights and no repair proof is usually not worth the headache, even if it looks cheap.
Related used car buying guides
Frequently asked questions
Is Cat N better than Cat S?
Usually, Cat N is seen as less risky because no structural damage was recorded. However, repair quality still matters, and a badly repaired Cat N car can still be a poor buy.
Does Cat S mean the car is unsafe?
Not automatically, but it means structural damage happened at some point. The quality of the repair must be checked carefully.
Should I avoid all Cat S and Cat N cars?
Not always. Some can be good value, but they need more checking than a clear-history car.
Are Cat S and Cat N cars cheaper?
Yes. They are usually cheaper than equivalent clear-history cars, but they are also normally worth less when you sell.
Should I get an inspection before buying?
Yes, especially with Cat S cars or any car where repair evidence is missing.
Can Cat N damage still be expensive?
Yes. Cat N means no structural damage was recorded, but the car may still have had expensive electrical, cosmetic, suspension or safety-system damage.
Will insurance be more expensive?
It can be. Always get quotes before buying because insurers may treat category cars differently.
Will a Cat S or Cat N car be harder to sell?
Usually yes. Some buyers avoid category cars, and others will expect a lower price.
What is the biggest red flag?
Missing repair evidence is one of the biggest red flags. If the seller cannot prove what happened and how it was repaired, be very cautious.
Is a cheap Cat S car worth it?
Only if the repair quality is proven, the car passes inspection, insurance is acceptable and the price is low enough to reflect the risk.