True-cost calculator

How it works

Total cost of ownership = depreciation (what the car loses while you own it) + fuel or energy + the age-indexed maintenance band + insurance. Depreciation is normally the biggest line of the four, which is why most "running cost" calculators — including the earlier version of this one — flatter every car by leaving it out. EV packs add a labeled out-of-warranty battery-replacement risk. Price, depreciation and insurance are class-level estimates; the formula and constants are published. Browse verdicts in the data index.

What the number is good for, and what it is not

The calculator answers one question: over the next few years, what will this model year cost to keep, compared with another? It is built for comparison — a 2015 against a 2018 of the same car, or a hybrid against the petrol version — because the inputs are class-level averages that cancel out when two cars of the same class are set side by side. It is not a quote for one specific car: condition, mileage, options and where you live move every line. The fuel figure is the EPA's, the maintenance band is an industry average indexed to the car's age, and the price, depreciation and insurance lines are estimates with a stated ±18% band. If you have been quoted a price, type it in on the model-year page and the whole panel recomputes from that number instead.

Where the inputs come from

Fuel economy comes from fueleconomy.gov (EPA). Maintenance bands are drawn from published industry cost-of-ownership surveys, indexed by vehicle age. The reliability score behind each verdict is computed from NHTSA complaint and recall records by the published method. Prices are re-priced to your country from retail fuel, electricity and parts indices; change the country in the bar at the top of the page and every figure follows.