Car running costs calculator

A car costs far more than fuel. Depreciation, insurance, tax, servicing, repairs, tyres and energy all add up. This calculator brings every item together and shows the cost per month and per kilometre — and, if you like, two vehicles side by side. Everything is worked out in your browser; nothing is stored.

Your result (vehicle A)

–

–Cost per month
–Cost per year
–Cost per km
–Largest cost driver

Cost types per year (vehicle A)

Cost types per year (vehicle A)
Cost type	per year

This calculator needs JavaScript because the calculation runs entirely in your browser – so your inputs never leave your device. A worked example is shown further down this page.

How this calculator works

Depreciation is treated as straight-line: (purchase price − expected resale value) ÷ holding period gives the yearly loss in value. Added to that are the yearly fixed costs (insurance, road tax as a free input, servicing, repairs and tyres) and the energy cost: annual km ÷ 100 × consumption × energy price. The yearly total divided by 12 gives the monthly cost; divided by the annual mileage it gives the cost per kilometre.

Road tax and every other cost are figures you enter yourself — the calculator holds no tax or insurance tables. The optional A/B comparison puts two vehicles next to each other; because consumption and energy price are free inputs, you can also compare an electric car with a petrol or diesel one (enter kWh/100 km and the price per kWh). Distances are metric (km) and consumption is per 100 km.

Formula and variables

Depreciation/year=(Purchase price − Resale value) / Holding years

Energy/year=Annual km / 100 × Consumption × Energy price

Total/year=Depreciation + Fixed costs + Energy

Cost per km=Total/year / Annual km

Purchase price: purchase price of the vehicle
Resale value: expected value at the end of the holding period (your estimate)
Holding years: planned holding period in years
Fixed costs: insurance + road tax + servicing + repairs + tyres per year
Annual km: annual mileage in km

Worked examples

Example: a used car kept for eight years

Example inputs
Purchase price	€24,000.00
Expected resale value	€9,000.00
Holding period	8 years
Annual mileage	10,000 km
Insurance / tax / servicing / repairs / tyres	550 / 120 / 300 / 400 / 180 per year
Consumption / energy price	5.5 l/100 km / 1.65 per litre

Example results
Cost per month	€361.04
Cost per year	€4,332.50
Cost per km	€0.43
Largest cost driver	Depreciation (1,875 per year)

Depreciation = (24,000 − 9,000) / 8 = €1,875.00 per year. Fixed costs = €1,550.00 per year. Energy = 10,000 / 100 × 5.5 × 1.65 = €907.50 per year. Total €4,332.50 per year, i.e. €361.04 per month and €0.43 per km. All figures are example assumptions.

Assumptions

Straight-line depreciation over the holding period (a simplification — in reality value often falls fastest early on).
Constant prices and costs within the scenario.
The resale value is your estimate, not a market valuation.

Limitations of this calculator

No tax or insurance tables and no model-specific figures.
No live vehicle data and no vehicle recommendation.
Real repair and depreciation paths vary.

Frequently asked questions

Why is depreciation often the biggest cost?

For newer cars the loss in value is often the most expensive item, yet it is easy to overlook because it is not billed each month. The calculator makes it visible. It uses a simplified straight-line assumption; in reality the value usually falls fastest in the first years.

Can I compare an electric car with a petrol one?

Yes. Switch on the A/B comparison and enter the second car's figures for vehicle B — consumption in kWh/100 km and the electricity price per kWh. You then see both total costs side by side.

Does the calculator save my car details?

No. Everything is worked out in your browser. Your entries are not stored and are not sent to a server.

Sources and further reading

Official and independent sources on this topic. The links open each website in a new tab; no content is loaded from them into this page.

Publication 946 – How to Depreciate Property (straight-line method)U.S. Internal Revenue Service (IRS)Authoritative description of the straight-line depreciation method used here for the yearly loss in value. Not tax advice.
Cost of running a carMoneyHelper (UK Money and Pensions Service)Consumer overview of the cost components of running a car (depreciation, insurance, fuel, servicing, tax). No live prices.

Spotted an error in the calculation or the text?

If you notice something that is wrong or unclear: let us know via the contact page. We review every report.

Last reviewed: 01/08/2026 · All calculations run in your browser – inputs are not stored. ·How we check our calculators