Car depreciation calculator
Estimate how much value your car has lost, forecast its future resale value and turn depreciation into an approximate monthly ownership cost.
Calculate car depreciation
Enter what you paid, what the car is worth now and the depreciation rate you want to test. The forecast is an estimate, not a guaranteed resale value.
What is car depreciation?
Depreciation is the fall in a car's value over time. You do not usually pay it as a bill, but it is still one of the biggest costs of owning a car because it reduces what you can recover when you sell or part-exchange.
For example, if you buy a car for £25,000 and later sell it for £17,000, the depreciation is £8,000. That lost value is part of the true cost of ownership, alongside fuel, insurance, servicing, tyres, finance interest and vehicle excise duty.
Car depreciation formula
The calculator measures the value already lost, then applies an annual depreciation rate to forecast future value.
Depreciation so far = purchase price - current value
Depreciation percentage = depreciation so far ÷ purchase price × 100
Future value = starting value × (1 - annual depreciation rate) ^ forecast years
Future loss = starting value - future value
Monthly depreciation = future loss ÷ forecast monthsIf you leave the current value blank, the forecast starts from the purchase price. If you add a current value, the forecast starts from that current value instead.
Worked depreciation examples
What affects car depreciation?
Depreciation is not perfectly predictable. Two similar cars can lose value at different speeds because buyers care about mileage, condition, model reputation, trim level, battery health for EVs, accident history, service records and market demand.
- Newer cars often lose value faster in the early years.
- High mileage can reduce resale value, especially if it is above typical annual mileage.
- Strong service history can help protect value.
- Popular models, desirable trims and lower running costs can improve resale demand.
- Finance type matters too, especially if you are comparing depreciation with PCP, HP or a personal loan.
Depreciation and the real cost of running a car
A car can feel cheap to run if fuel costs are low, but depreciation may still make it expensive overall. A useful check is to combine this calculator with the Fuel Cost Calculator, Commute Cost Calculator and Car Finance Calculator.
That gives a fuller view of the cost per month: fuel or charging, finance, insurance, maintenance, tax and the value you are likely to lose over the time you own the car.
Compare the car's real monthly cost
Depreciation is only one part of ownership. Use the running-cost guide to compare fuel, finance, insurance, depreciation and other costs before deciding what a car really costs you.
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Car depreciation calculator FAQs
How do I calculate car depreciation?
Subtract the car's current value from the purchase price. Divide that value loss by the purchase price and multiply by 100 to get the depreciation percentage.
What annual depreciation rate should I use?
There is no single correct rate. A rough scenario may use 10–20% per year, but the right figure depends on age, mileage, condition, make, model and market demand.
Is depreciation a real cost?
Yes. You may not pay it monthly, but it is a real cost because it reduces the amount you can recover when selling or part-exchanging the car.
Can a car go up in value?
Some cars can hold or increase value, especially rare or desirable models, but most everyday cars lose value over time. If your current value is higher than the purchase price, the calculator will show no depreciation so far.
Related glossary terms
These glossary pages explain the ownership-cost terms used in this calculator.