Electric vs Petrol Running Cost Calculator
Enter your yearly miles and the economy of each car. You get the cost a mile, the cost a year, the saving and how long a higher purchase price takes to pay back.
This is an estimate. The prices shown are examples, so use today's prices and your own car.
Worked examples
Ten thousand miles
45 mpg at 145p a litre against 3.5 miles per kWh at 25p, all home charging
Petrol £1,465, electric £714, saving £751 a year
A £3,000 higher price pays back in about 4 years.
About Electric vs Petrol Running Cost Calculator
An electric vs petrol running cost calculator compares the fuel bill for two cars. The cost a mile of a petrol or diesel car is the price of a litre, times 4.546 litres in an imperial gallon, divided by the miles per gallon. For an electric car it is the price of a kWh divided by the miles you get from each kWh. The tool works out both for a mile and for a year of driving.
Because home charging is much cheaper than public charging, the share of charging you do at home has a big effect on the result, so you enter the price of each and the share. If the electric car costs more to buy, enter the difference and the page shows how many years of fuel savings it takes to cover it. Only fuel and electricity are counted, not insurance, servicing, tyres, road tax or depreciation.
How to use Electric vs Petrol Running Cost Calculator
- Enter your yearly miles.
- Enter the miles per gallon and the fuel price for the petrol or diesel car.
- Enter the miles per kWh, the home and public prices and the share at home for the electric car.
- Read the cost a mile, the cost a year, the saving and the payback.
Common uses
- Deciding whether to switch to electric
- Choosing between company cars
- Checking a salary sacrifice scheme
- Comparing a hybrid with a petrol car
Frequently asked questions
Is an electric car cheaper to run than petrol?
Usually, if you can charge at home. At 45 mpg and 145p a litre petrol costs 14.6p a mile. An electric car at 3.5 miles per kWh and 25p a kWh costs 7.1p a mile, so 10,000 miles saves about £751 a year.
What if I use public chargers?
Public rapid chargers can cost several times more than home. At 70p a kWh the electric car costs 20p a mile, more than the petrol one, so the share charged at home matters most.
How long to pay back a dearer electric car?
Divide the extra price by the yearly saving. A £3,000 price difference with a saving of £751 takes about 4 years.
Are mpg figures the same everywhere?
No. This tool uses imperial gallons as on UK car labels. A US gallon is smaller, so US mpg figures need converting first.
What is not included?
Insurance, servicing, tyres, tax, depreciation and the cost of a home charger are not included, so treat the result as the fuel comparison only.