Vehicle finance and running cost calculator
Work out what a used car, van, motorbike or motorhome really costs: the monthly finance payment, the total interest over the agreement, fuel or charging for your mileage, and a depreciation estimate. All figures update as you type and nothing is sent to a server. The same maths powers the per-listing cost estimates when you save listings to a shortlist.
Purchase and finance
Fuel or charging
Assumes a national average pump price of £1.56/litre.
Results
- Monthly payment
- £271
- Total interest
- £2,218
- Total payable
- £14,218
- Fuel / year
- £1,261
- Est. 3-yr depreciation
- £3,822
- 3-yr running total
- £9,661
The 3-year running total is depreciation + fuel + finance interest paid in the first 36 months. Road tax, insurance, servicing and ULEZ are excluded here; the app estimates road tax and ULEZ per listing.
How the calculation works
Finance: UK lenders quote APR as an effective annual rate, so the monthly rate is (1 + APR)^(1/12) − 1 rather than APR ÷ 12. The monthly payment is the standard amortised repayment on the amount financed (price minus deposit), and total interest is what you pay beyond the amount borrowed. Real quotes may add arrangement or option-to-purchase fees, and PCP agreements with a balloon payment work differently: this calculator models a straightforward hire-purchase style loan.
Fuel: annual mileage divided by MPG gives gallons per year, converted at 4.546 litres per UK gallon and multiplied by the national average pump price. Electric vehicles use miles per kWh at the Ofgem price-cap home rate; public rapid charging costs two to three times more.
Depreciation: an exponential decay per vehicle type (cars lose roughly 12% of their current value per year, vans 10%, motorhomes 7%). Used prices curve rather than fall in a straight line, which is why a three-year-old car has lost far more than a car going from seven to ten years old. See our guide to total cost of ownership for the full picture.
When you save real listings, CompareForecourt runs these numbers for every vehicle automatically, adds road tax and ULEZ, sharpens the depreciation estimate using same-model listings in your shortlist, and includes your own finance terms from Settings. See how it works and where the data comes from.