What would an electric car save you on fuel?
Pick your current car or van and the EV you have in mind, then add what you pay at the pump and how far you drive. Home charging is priced at 9p per kWh.
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Disclaimer
This calculator is a free tool and gives an indication only. It is not a guarantee, a quote, or financial, tax or purchasing advice. Fuel and energy figures come from official test data or, where you use the lookup, an automated online search, so they may be out of date, incomplete or wrong. Figures marked “estimate” are for models not yet on sale and may change once official figures are published. Real-world use depends on how and where you drive, the weather and the condition of the car, and fuel and electricity prices change. Only fuel and home-charging costs are compared; insurance, tax, servicing, depreciation, finance and public charging are not included. To the extent permitted by law, Car Buying and Selling accepts no liability for decisions made using these results.
The description you type into the lookup is sent to an AI service (Anthropic) to find the figure, so please do not enter personal details such as your name or registration number.
Electric costs assume all charging at home at the rate shown. Weekly figures are the annual total divided by 52, monthly by 12. Fuel costs only: insurance, tax, servicing, depreciation and public charging are not included.
How the calculator works
The sums behind the calculator are simple, and you can check them yourself. Your annual miles divided by your mpg gives the gallons you burn each year.
A UK gallon holds 4.546 litres, so that figure becomes litres, then pounds at your pump price. On the electric side, miles divided by miles per kWh gives the electricity used.
Multiply that by your home charging rate and you have the cost of running the EV. The gap between the two totals is your saving.
Vehicle figures come from official test data published by the Vehicle Certification Agency and the European Environment Agency. Newer cars use the WLTP test. Older cars use the earlier NEDC test, which flatters real-world economy, and models not yet on sale, such as the Kia PV7, are marked as estimates. If yours isn’t listed, describe it and the lookup will search for the figure.
A real example: petrol Peugeot to electric SUV
My own switchBefore going electric, I leased a Peugeot 408 PureTech GT with the 1.2-litre petrol engine. Its official economy figure is 43.8 mpg.
I now drive a Changan Deepal S07, which returns about 3.3 miles per kWh in UK road tests. I cover roughly 10,000 miles a year.
I charge at home on Octopus Intelligent, which costs me 10p per kWh. Petrol is priced at the UK average of 173.5p per litre from late September 2026.
| 10,000 miles a year | Used | Cost |
|---|---|---|
| Peugeot 408 PureTech (petrol, 43.8 mpg) | 1,038 litres | £1,801 |
| Deepal S07 (electric, 3.3 mi/kWh) | 3,030 kWh | £303 |
| Fuel saving | £125 a month | £1,498 a year |
That works out at almost £29 a week. Across a typical three-year lease, the fuel saving alone comes to around £4,500.
A real example: diesel van to electric van
My sister’s switchMy sister ran a 2020 Ford Transit Custom with the 2.0-litre diesel engine. She covers about 15,000 miles a year, almost all of it around the city.
I talked her into a Kia PV5 Long Range, and like me she charges it at home. Diesel is priced at the late-September UK average of 197.6p per litre.
| 15,000 miles a year | Used | Cost |
|---|---|---|
| Ford Transit Custom (diesel, 38 mpg) | 1,795 litres | £3,546 |
| Kia PV5 Long Range (electric, 3.25 mi/kWh) | 4,615 kWh | £462 |
| Fuel saving | £257 a month | £3,084 a year |
Her saving is double mine for two reasons. She drives further each year, and diesel now costs over 20p a litre more than petrol.
The table is also on the cautious side. Stop-start city traffic drags a diesel van well below its official mpg figure.
An electric van does the opposite in town, recovering energy every time it slows down. Her real-world saving is likely higher than shown here.
Why your charging rate matters most
Almost all of the saving depends on charging at home, overnight, on a cheap EV tariff. That is the setup both examples above use.
Public rapid chargers cost several times more per kWh than an off-peak home tariff. A driver who relies on them will save far less, and sometimes nothing at all.
Try raising the charging rate in the calculator to see how quickly the gap narrows. It is the quickest way to stress-test your own numbers.
What the calculator leaves out
This tool compares fuel and home charging costs only. Insurance, road tax, servicing, depreciation and finance all shape the full cost of a switch.
Electric cars now pay road tax like any other car, and insurance can cost more on some models. Servicing is often cheaper, with no oil changes and less brake wear.
The biggest number is usually the monthly price of the car itself. The Leasing.com link above lets you compare electric lease deals side by side.
If a dealer has already given you a price, my Deal Analysis Report will show you where it can be improved before you sign.
Questions people ask
How accurate are the results?
They are a good guide, not a guarantee. Official test figures are a fair starting point, but cold weather, motorway speeds and heavy loads all cut efficiency.
EVs lose more range in winter than petrol or diesel cars, so expect your electric costs to rise a little between November and February.
Should I use the official mpg or my real mpg?
Use your real figure if you know it. Most cars show average mpg on the trip computer, and that number reflects how you actually drive.
Why is the home charging rate set to 9p per kWh?
It sits close to what many overnight EV tariffs charge. If you pay more or less, change the figure and the results update straight away.
Does the calculator work for vans?
Yes. Popular diesel and electric vans are included, using official data for light commercial vehicles from the European Environment Agency.
My car isn’t in the list. What should I do?
Describe it in the lookup box, for example the make, model, year and engine size. You can also type the mpg or miles per kWh in yourself.
Can fuel savings really pay for an electric car?
For high-mileage drivers, they can cover a large share of it. My sister’s £257 a month saving would go a long way towards a typical electric lease payment.
Run your own numbers above, then compare lease prices to see how close you get.