Insurance write-off categories (A, B, S and N) explained

If you buy vehicles at salvage auctions, you'll see categories A, B, S and N. They tell you how badly the vehicle was damaged and what can lawfully happen to it next, and they change what it's worth.

The four categories

Categories S and N replaced the older C and D categories in 2017, and the classification stays with the vehicle's record for life.

Cat N doesn't mean minor

"Non-structural" describes where the damage is, not how much of it there is. A Cat N vehicle can have serious damage to non-structural parts, including safety-related ones such as brakes, steering or airbags, and these have to be put right properly.

Why it changes your numbers

• Resale value. Written-off vehicles tend to be worth less than comparable vehicles that haven't been, and Cat S can be harder to sell.
• Insurance. Some insurers are more cautious about written-off vehicles, particularly Cat S, which can affect buyers.
• Repair cost. Structural repairs are usually more specialised and more expensive.

A worked example

You buy a salvage car at £1,000 as a low volume Copart buyer who bid ahead of the auction. Your all-in cost at the auction is £1,400.80 (see Copart UK fees explained). You estimate £1,200 of repairs. The resale price is the big unknown:

A £500 difference in the resale price halves the margin. If the category might make the car harder to sell, use the cautious figure.

Before you bid

• Check the category shown for the lot, and don't rely on the photos alone.
• Run a vehicle history check.
• Get repair quotes where you can, and add a margin for surprises.

General information only, not tax or financial advice. Auction houses set their own fees and terms, so always check the conditions of sale and confirm the details with the auction house before you bid. Always run a vehicle history check and, if possible, get the vehicle inspected before you bid.