Compare Car Costs

What a car really costs only shows once you add everything up: depreciation, fuel or electricity, and fixed costs such as insurance, tax and maintenance. An electric car often costs more to buy but less to run; a petrol car is cheaper to buy but costs more per kilometer. That is why the costs of two cars do not rise at the same pace. This calculator adds them up month by month and shows where the lines cross.

For each car the calculator adds up three items every month. Depreciation is a fixed percentage per year of the remaining value; between two whole years it uses a fraction of a year. The energy cost is the distance per month × the consumption ÷ 100 × the energy price. The fixed costs are added every month. The break-even point is the moment both cars have cost the same in total; if it falls between two whole months, it is estimated with a straight line between those months. The difference is the total cost of car B minus that of car A at the end of the period: positive means car A is cheaper, negative means car B is cheaper. A distance in miles is converted to kilometers first.

• Depreciation is the same percentage of the remaining value every year.
• Consumption, energy price and fixed costs stay the same for the whole period.
• Both cars cover the same distance per year.
• Interest on a car loan, or interest lost on savings, is not included.
• Subsidies, company car tax and one-off costs only count if they are included in the purchase price or the fixed costs.
• A break-even point between two whole months is estimated with a straight line.

The button fills in the calculator above, so you can carry on from there.

• Petrol vs electric

  Difference: car B minus car A

  -$7,780.35 · Car B is cheaper over this period

  Car A purchase price $30,000.00 · Car B purchase price $48,000.00 · Car A consumption per 100 km 6.5 · Car B consumption per 100 km 17.5 · Car A energy price $2.05 · Car B energy price $0.38 · Car A fixed costs per month $200.00 · Car B fixed costs per month $150.00 · Car A depreciation per year (%) 15 · Car B depreciation per year (%) 15 · Distance per year 20,000 km · Period (years) 12

  A petrol car at 30,000 against an electric car at 48,000, driving 20,000 km a year.

• High mileage: diesel vs petrol

  Difference: car B minus car A

  $6,764.18 · Car A is cheaper over this period

  Car A purchase price $36,000.00 · Car B purchase price $27,000.00 · Car A consumption per 100 km 4.8 · Car B consumption per 100 km 6.8 · Car A energy price $1.90 · Car B energy price $2.05 · Car A fixed costs per month $230.00 · Car B fixed costs per month $190.00 · Car A depreciation per year (%) 15 · Car B depreciation per year (%) 15 · Distance per year 35,000 km · Period (years) 12

  A diesel at 36,000 against a petrol car at 27,000, driving 35,000 km a year.

• Small city cars

  Difference: car B minus car A

  -$2,049.07 · Car B is cheaper over this period

  Car A purchase price $15,000.00 · Car B purchase price $24,000.00 · Car A consumption per 100 km 5.5 · Car B consumption per 100 km 14.5 · Car A energy price $2.05 · Car B energy price $0.40 · Car A fixed costs per month $130.00 · Car B fixed costs per month $100.00 · Car A depreciation per year (%) 14 · Car B depreciation per year (%) 14 · Distance per year 8,000 km · Period (years) 12

  A small petrol car at 15,000 against a small electric car at 24,000, driving 8,000 km a year.

Last reviewed: 4 October 2026

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