EV vs Petrol Running Cost Calculator
Compares what an electric car and a petrol car cost to fuel over a year, and how long a higher purchase price takes to repay. Fuel only — insurance, servicing and depreciation differ too, and usually favour the EV on servicing and the petrol car on depreciation.
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
The formula
saving = petrol fuel cost − EV energy cost, both over the same annual distance
The EV side divides by charging efficiency, because you are billed for energy drawn from the wall rather than energy stored. Leaving that out flatters the EV by around 10%.
What to watch out for
The comparison turns on two numbers you control:
- Your electricity tariff. Off-peak EV rates can be a third of the standard rate. The same car on the same journey can cost three times as much to run depending only on when it charges.
- Where you charge. Someone relying on public rapid charging may save little or nothing against an efficient diesel. The EV running-cost case is largely a home-charging case.
This is fuel against energy only. Servicing is usually lower on an EV — no oil, fewer moving parts, less brake wear from regeneration — while depreciation and insurance have historically been higher. Include those separately before deciding.
Frequently Asked Questions
Is an electric car cheaper to run?
On home charging, almost always — commonly a half to a third of petrol per mile. On public rapid charging alone, the advantage largely disappears against an efficient diesel.
How long does it take to recoup the higher price of an EV?
Enter the price difference and the calculator divides it by the annual fuel saving. At 16,000 km a year with a typical saving, a modest premium repays in three to six years; a large one may outlast your ownership.
Does this include servicing and insurance?
No — fuel and energy only. EV servicing is generally cheaper; insurance and depreciation have tended to be higher. Add those separately for a full picture.
Why divide by charging efficiency?
Because the meter bills what leaves the wall, not what reaches the battery. At 90% efficiency you pay for about 11% more energy than you store, and ignoring it overstates the EV saving.