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Running Costs
Car Running Cost Calculator
Fuel is only part of the story. This works out the real cost of running a car, depreciation, fuel or electricity, insurance, road tax and servicing combined, as an all-in pence-per-mile and a yearly figure, for petrol, diesel or electric.
What a car really costs to run
Most people budget for fuel and forget the rest. The true cost of running a car is five things added together:
- Depreciation — the value the car loses while you own it. Usually the biggest cost, and the one with no monthly bill to remind you.
- Fuel or electricity — worked out from your MPG (or miles per kWh) and the price you pay.
- Insurance, road tax (VED) and servicing & maintenance — the standing costs that arrive every year.
Add them up, divide by your annual mileage, and you get the honest figure: all-in pence per mile.
Why depreciation usually wins
A £20,000 car worth £12,000 after three years has lost £8,000 — about £2,667 a year. For an average driver that often beats the fuel bill outright. It's why a car that holds its value can be cheaper to own than a thirstier car that depreciates slowly, and why chasing a few extra MPG rarely moves the needle as much as buying well.
Petrol, diesel or electric
Switch the fuel type and the calculator swaps to the right inputs — MPG and pump price for petrol/diesel, miles per kWh and electricity price for an EV. To compare two cars fairly, run each one and compare the all-in cost per mile, not just the energy cost, because depreciation, insurance and servicing can differ a lot between them.
Frequently asked questions
What does it cost to run a car per mile?
All-in, a typical petrol car is often 50–70p per mile once depreciation, fuel, insurance, tax and servicing are included — far more than the fuel-only figure. Your result depends entirely on your own numbers.
Why is depreciation counted as a cost?
Because it's real money lost. If a car drops £8,000 in value over three years, that's £8,000 you don't get back — usually more than you spend on fuel.
How is cost per mile calculated?
Total yearly cost (depreciation + fuel + insurance + tax + servicing) ÷ annual mileage × 100 = pence per mile. The breakdown shows each part's share.
Is an EV really cheaper to run?
Usually on energy per mile, especially overnight charging. But compare the all-in figure — depreciation, insurance and servicing matter too. Switch the fuel type and enter each car's figures.