The Index over time · since 2026-07
Which way is depreciation moving?
Every month Forecourt snapshots the full Depreciation Index — median three-year value retention across 267 UK models. As of 2026-09, the typical car keeps 60% of its value over three years — and the median petrol car keeps 20 percentage points more than the median electric one. Each first Monday adds a point, building a retention record no one else keeps.
Median three-year retention, month by month
— All cars– Electric– Petrol– Diesel– Hybrid
Latest reading — 2026-09
| Fuel | Models | Median kept · 3yr |
|---|---|---|
| diesel | 25 | 56% |
| electric | 66 | 50% |
| hybrid | 144 | 62.5% |
| petrol | 32 | 70% |
Retention is each model's share of value kept at three years, from the same per-model curves and list prices behind every profile; new models priced only from launch list are excluded. Free to cite with attribution.