You supply the price
A UK original new price for the car's registration year anchors the calculation. A price range lets you explore uncertainty about the exact version.
DATA LAB / CAR VALUATION
What might your car
be worth?
Help test a free valuation model. Start with its original new price, add age and mileage, then compare the estimate with a price you know.
UK cars · GBPFree research betaModel snapshot: 19 October 2026
For ordinary petrol and diesel cars aged 1–15 years at this snapshot. Current-market accuracy is unvalidated; use this as a research estimate, not an insurance quote or agreed value.
01 / TRY YOUR CAR
Build your estimate
02 / HELP IMPROVE THE MODEL
How does it compare?
If you know a price for the same car, add it below. A reported price is a test observation and will need review before it can be used to calibrate the model.
03 / UNDERSTAND THE ESTIMATE
From original price to an estimated value
Age and mileage adjust it
Depreciation curves learned from historical asking prices reduce the value. Model-family curves are used where there is enough data, with broader curves as a fallback.
You test the result
A frozen ONS market factor adjusts the historical shape. Compare the result with evidence you know and share your observations.
Review downloaded feedback by cohort and evidence type → · Evaluation-data register →
Scope and limitations
The calculator accepts UK petrol/diesel cars aged 1–15 at the snapshot (registration years 2011–2025), 0–200,000 miles, 0.7–5.0 litre engines and original prices £3,000–£150,000. It excludes hybrids, electric vehicles, declared specialists and estimates over £80,000. These are research limits, not validated coverage.
There are 177 model families across nine makes in the historical fit, with 47 dedicated family curves. Other cars borrow a group or pooled curve and carry an explicit warning. Trim, generation, condition, optional equipment and exact registration date are not modelled. Age uses calendar years.
The shape is normalised to the supplied new price. The relationship between verified original prices and used prices, including the first-owner discount, has not been calibrated. The displayed range shows only the effect of your input-price range; it is not a statistical prediction interval. A precise input does not imply a precise valuation.
The API's default quote mode still returns customer entry. This public test does not prefill insurance values or produce binding valuations.
What has actually been tested?
The curves were fitted to 66,081 historical petrol/diesel asking-price records. A historical family-transfer experiment tested 2,761 older cars from 10 model families, using near-new asking prices as proxies for their new prices.
| Curve | Median absolute percentage error |
|---|---|
| Grouped depreciation | 10.11% |
| Pooled depreciation | 9.37% |
| Fixed 15% annual comparator | 16.07% |
No winning variant was chosen from that test. There are currently zero independently validated current individual vehicles and zero verified historical original-price anchors in this release. Public feedback is intended to help close those evidence gaps.
Sources, snapshot and reproducibility
Model: price-anchor-shape-v1, built 19 October 2026. Historical data: Aditya Desai's publisher-labelled CC0 UK used-car dataset, assumed 2020 observation cohort. Upstream advert-source rights have not independently been established. This page publishes derived coefficients, not raw adverts.
ONS D7E9: August 2026 index 109.4, released 16 September 2026. Assumed June 2020 base 96.5; factor 1.13368. This broad market adjustment does not validate the price of an individual car. Contains public sector information licensed under the Open Government Licence v3.0. Opening the page later does not refresh its data.
The latest calculator does not use Autoza, current replacement-price leads or a paid valuation feed. The earlier model and its Autoza comparison remain available separately.
Historical dataset · ONS series · Model coefficients · Model and API notes