How this estimate is built
Both modes apply the same declining-balance depreciation curve, commonly used across UK valuation guides: roughly 25% lost in year one, 15% in year two, 12% in year three, then 8% a year through years four to six, 5% a year through years seven to ten, and 3% a year beyond that. This reflects the well-documented pattern that depreciation is steepest when a car is newest and flattens significantly with age.
By registration pulls the car's real first-registration date and its actual mileage history across every recorded MOT test, so the age and average-mileage figures used are genuine, not typed-in guesses. It also checks the car's real defect record: a history of dangerous defects or advisories that repeat across multiple tests nudges the estimate down, since that's a genuine, documented condition signal, while a clean record with no repeated issues nudges it up slightly. None of this is a substitute for real market comparables, but it is real data about the specific car rather than an assumption.
Manual entry uses the same depreciation curve and a simpler mileage comparison against the roughly 10,000 miles/year UK average, useful for a hypothetical car you don't have a registration for yet.
What neither mode can account for: the specific make and model's own resale reputation, current local market demand, and anything about the individual car's history or presentation that isn't in its MOT record. A handful of specific things worth weighing yourself against the range above:
Can push it toward the top of the range
- Full service history, especially with the same garage or main dealer throughout
- Desirable spec or colour for that model
- Genuine low mileage for its age, already factored in if you used the registration lookup
- No visible damage beyond ordinary wear for its age
Can push it toward the bottom of the range
- Gaps in service history, or no MOT history at all beyond the legal minimum
- A high number of previous keepers for the car's age
- Non-working features, electric windows, seat heaters, and similar
- Significant wear or damage beyond what's typical for the mileage
This isn't a fixed adjustment, since we don't have data on any of these for a specific car beyond its MOT record, it's a checklist for judging where in the range above a real car likely sits.
Frequently asked questions
Is this an accurate car valuation?
No. There is no free, publicly available UK car valuation data source, so this tool applies a typical industry-wide depreciation curve, adjusted using real MOT data where a registration is provided, rather than a real market price. It gives a more grounded ballpark than a manual guess, not a figure to price a sale or purchase against.
How much does a car actually depreciate in the UK?
Typically 15 to 25 percent in the first year, reaching 40 to 60 percent lost by three years old, then slowing to around 5 to 8 percent a year through mid-life, and 3 to 5 percent a year once a car passes 8 to 10 years old.
Why do I still need to enter the original price myself?
Original list price isn't held in any free UK government dataset, DVSA and DVLA records cover MOT and tax history, not what a car cost when new, so this is the one figure that has to come from you, ideally from the original invoice, a similar car's brochure price, or a specialist site that tracks historic new car pricing.