Cat S vs Cat N write-offs explained
By Plateworthy · Updated · Editorial policy
If a car has been in an accident and the insurer decided it wasn't economical to repair, it gets a write-off category. Cat S and Cat N are the two you'll see most often on cars that are back on the road. Here's what each one means in plain English.
What the categories mean
Cat S (Structural) means the car suffered structural damage (to the chassis, crumple zones or another load-bearing part) which can be repaired. The category does not establish that a repair happened or was safe.
Cat N (Non-structural) means the damage did not affect the structure. It can still be significant (electrics, steering, airbags, or cosmetic damage that cost more to fix than the car was worth), but the category does not establish the car's present condition.
Older categories (Cat C and Cat D) were replaced by Cat S and Cat N in 2017. You may still see C and D on cars written off before then.
Are they safe to buy?
A properly repaired Cat S or Cat N car can be perfectly safe and is often a lot cheaper than an equivalent unrecorded car. The risk is a bad repair, so the quality of the work matters more than the category itself.
Always get an independent inspection, ask to see repair invoices and photos of the damage, and be realistic that the car will be worth less when you come to sell it.
How to check before you buy
The write-off marker is held in the same industry data as outstanding finance and theft records. It is not in the free MOT data, so a free check alone won't show it.
Run a full history report before you pay a deposit. It can show the recorded category and, where supplied, the insurer, damage information and date. Missing details are not proof that no damage occurred.
Common questions
- Does a Cat S or Cat N car need a new MOT?
- There's no automatic re-test purely for the category, but the car must be roadworthy and have a valid MOT like any other vehicle. A fresh MOT after repair is reassuring but not a guarantee of repair quality.
- Will the write-off show on a free car check?
- No. Write-off categories come from insurance industry data, not the free government MOT records, so they only appear in a paid full history report.
- Is Cat N safer than Cat S?
- Cat N damage is non-structural, so on paper it's less serious than Cat S. But a poorly repaired Cat N car can still be unsafe, and a well-repaired Cat S car can be fine. The repair quality matters most.
Sources and further checks
Primary guidance checked for this update. Rules and individual circumstances can change; use the linked official service or advice where a decision depends on it.