Insurance

What Valuation Guides Do Insurers Use for a Write-Off?

Published 12 October 2026 · 6 min read

Insurers value a written-off car with motor trade valuation guides, and the Financial Ombudsman Service checks their offer against the same kind of guides, naming AutoTrader, CAP, Cazana and Glass's. If the guides agree and the offer matches them, the Ombudsman is likely to agree with the insurer. If they differ a lot, it looks for other evidence.

This guide explains how the guides are used, what the Ombudsman does when they disagree, and what counts as evidence against an offer. It is based on the Ombudsman's own pages and on published decisions.

Offer looks low? Get a price for a write-off valuation report.

Which valuation guides do insurers use?

Motor trade valuation guides: databases that estimate what a given car would sell for, from advertised and auction prices, adjusted for specification, extras and mileage. The Ombudsman names four it compares offers with: AutoTrader, CAP, Cazana and Glass's. Insurers do not all use the same combination. One policy quoted in an Ombudsman decision says its market value "is based on research from industry recognised motor trade guides", without naming any.

How current the figures are depends on the guide. In a 2022 decision the Ombudsman said it uses three guides that are used across the insurance industry, that two update their data daily and the third monthly (DRN-3414585). That answers a common objection, that the guides run on old data.

What does "market value" mean on a write-off?

The Ombudsman describes it as the price the vehicle would have sold for at a reputable dealership just before it was damaged or stolen. Policies phrase it in their own way. In one decision the policy defined it as the cost of replacing the car with one of a similar make, model, year, mileage and condition, based on market prices immediately before the loss (DRN-3414585).

Two points follow. The figure is not what you paid or what you declared on the policy: the Ombudsman says the value you estimated on the application is not the amount an insurer has to pay out. And it is the value immediately before the loss, not today's replacement cost. A customer in that decision pointed to prices months after the loss, and the Ombudsman did not accept that, because the policy covers the value immediately before the loss.

What does the Ombudsman do when the guides disagree?

It checks whether the insurer's valuation is backed by other evidence. Its consumer page says that if the guides all give a similar value and the insurer's figure is in line with them, it is likely to agree. Where the guides vary significantly, it looks at whether the insurer's valuation is supported by adverts or an expert's opinion. If the valuation is unfair, it tells the insurer to adjust it to the highest value in the guides, or to the value the other evidence supports, whichever is fairest.

A 2024 decision shows how that works in numbers (DRN-4841911):

Step	Amount
Values from four guides	£11,390, £11,676, £11,795 and £12,942
Insurer's starting valuation	£11,869, towards the lower end
Insurer's offer (average of the guides, less 20% for a previous write-off)	£9,985
Ombudsman's figure: highest guide, less the same 20%	£10,354, plus 8% simple interest on the shortfall

The insurer had not shown why a lower figure was fair, so the Ombudsman started from the highest guide. The 20% deduction for the earlier write-off was accepted, but applied to the higher number. The customer thought the car was worth over £15,000 and sent no evidence, so the decision stayed with the guides.

Guides give a figure. A valuation report shows the working. We prepare an independent valuation from the details and photos you send, with the comparable cars and the adjustments set out, usually within a few hours.

Get a price for my write-off valuation report

Your price is confirmed in writing before any work begins.

What evidence counts against the insurer's figure?

The Ombudsman says it may ask for independent engineer or expert reports (including details of modifications), copies of motor valuations, a repair estimate, evidence of pre-existing damage and the vehicle's history. On adverts, it says it did not use to give them weight, but the guides have told it that cars now sell at or close to advertised prices, so it typically considers them. The condition is that they are like for like: mileage and year of registration can change the value of the same model a great deal.

That condition decides cases. In DRN-3414585 the guides gave £12,900 to £13,537 and the insurer offered £12,950. The customer wanted £14,000 to £15,000 and sent adverts. The Ombudsman noted that the higher-priced cars in the closest-match list mostly had lower mileage than his, found similar cars with 50,000 to 80,000 miles at £11,700 to £13,500, and did not uphold the complaint. Higher prices for lower-mileage cars did not help.

What if the guides do not cover the car?

The Ombudsman says the guides do not usually value vehicles over 20 years old, and may not value unusual vehicles or conversions such as campers. Then it asks for other information, such as an engineer's report.

One case study shows why that matters (classic motorbike case study). A stolen motorbike was over 25 years old and only one guide valued it. The insurer had checked nothing else, and that guide said it did not normally value bikes that old because the values were inaccurate. The customer produced adverts and an online valuation. The Ombudsman told the insurer to settle on the fairer online valuation and to pay interest on the difference. For a classic or unusual car, a single guide figure is a weak basis for an offer. Our guide to insuring a modified, imported or classic car covers the policy side.

Which deductions are normal?

Some are accepted if the insurer can support them. The Ombudsman says a left-hand-drive car, or an imported right-hand-drive one, is usually worth less in the UK, so a deduction is normally fair but the insurer should show evidence for it, and a deduction would not apply to a classic car. A previous write-off can justify a reduction, as the 20% above shows. Pre-existing damage counts only if it would have affected the market value: the Ombudsman's example is that small scratches might matter on a new car but not on one 15 years old. Keeping the car brings a separate salvage deduction, and only Category N and S cars can be kept (GOV.UK, insurance write-offs). It is covered in our guide to keeping a written-off car.

What should you do if the offer looks low?

Ask the insurer which guides it used, what each gave, and how it reached its figure.
Check the make, model, year, mileage and specification it recorded. The Ombudsman says it sees valuations based on wrong details recorded by insurers and customers.
Collect adverts for cars that match yours on year, mileage and specification, as close to the date of the loss as you can.
Complain to the insurer first. If you are not satisfied you can take it to the Financial Ombudsman Service.

Our guide on what to do if a write-off offer is too low goes through the complaint route, and the one on what makes a valuation report defensible explains what a written valuation should contain.

Frequently asked questions

What valuation do insurance companies use for a write-off?

Insurers use motor trade valuation guides to estimate the car's market value just before the loss. The Financial Ombudsman Service compares an insurer's valuation with online guides such as AutoTrader, CAP, Cazana and Glass's when a customer says it is too low.

What happens if the valuation guides give different values?

The Ombudsman looks at whether the insurer's figure is backed by other evidence, such as adverts or an expert's opinion. If it is not, it can tell the insurer to use the highest value in the guides, or the value the other evidence supports, whichever is fairest.

Can I use adverts to argue my car is worth more?

Yes, if they are like for like. The Ombudsman says it now typically considers adverts, but mileage and year of registration can change a value a lot, so the adverts need to match your car's specification as closely as possible.

What if my car is too old for the valuation guides?

The Ombudsman says the guides do not usually value vehicles over 20 years old, or unusual vehicles and conversions. In that case it asks the insurer and the customer for other information, such as an engineer's report.

Car written off and the offer looks low?

Send us the details and photos and we prepare an independent valuation with the comparable cars and the adjustments set out in writing, usually within a few hours.