Free comparison tool
EV vs petrol cost calculator
How much could switching to electric save you? Set your mileage and the rates you actually pay to compare a year of charging against a year of fuel, and the cost per mile for each.
Fuel cost only. Excludes tax, insurance, servicing and depreciation. Pump and electricity prices change, so edit them to today's rates.
How the comparison works
We work out a year of energy for each car and price it up. For the electric car, your annual miles divided by efficiency gives the kWh needed; we add charging losses and multiply by a blended rate that mixes your home and public prices in the proportion you set. For the petrol or diesel car, your miles divided by mpg gives the gallons, which we convert to litres and multiply by the pump price.
The difference is your yearly saving, and dividing each annual cost by your mileage gives the cost per mile. Every figure is editable, so the comparison reflects your car, your tariff and today's pump price rather than a national average.
Why home charging is the deciding factor
The single biggest lever is where you charge. On an off-peak EV tariff near 7p/kWh, an efficient EV costs around 2p per mile. The same car relying on public rapid chargers at 80p/kWh can cost over 20p per mile, similar to petrol. Most drivers sit near the home end, which is why the EV usually wins comfortably, but the slider lets you be honest about your own mix.
What we have left out
This is a fuel-versus-electricity comparison, not a total cost of ownership. It does not include the purchase price, insurance, servicing, tyres or depreciation. EVs tend to be cheaper to service and, at the moment, to tax, while petrol cars are often cheaper to buy. A per-mile tax on electric cars has been signalled for around 2028; it is not yet in force, so it is not included here.
Getting an accurate result
For the fairest comparison, use your car's real efficiency from its trip computer over a few weeks, your actual electricity rates from your bill, and the mpg you really see rather than the brochure figure. Small changes in efficiency and the home-vs-public split move the result more than anything else.
Once you have chosen an EV, the charging cost calculator breaks down a single charge, and the charging time calculator shows how long it takes.
Common questions
- Is an electric car cheaper to run than petrol?
- On fuel, almost always yes, especially if you charge at home on an off-peak tariff. A typical EV costs a few pence per mile in electricity against roughly 12 to 16p per mile for petrol. The gap narrows if you rely heavily on public rapid chargers, which is why the home-vs-public split matters.
- What efficiency should I use for the EV?
- Real-world efficiency is usually between 2.5 and 4.5 miles per kWh. A small efficient EV in mild weather can beat 4; a large or performance model in winter can drop below 3. We default to 3.7 as a middle value, but set your car's figure for an accurate comparison.
- Why does the home vs public split matter so much?
- Home electricity, especially off-peak, is a fraction of the cost of public rapid charging. Charging mostly at home keeps the per-mile cost very low; charging mostly in public brings it closer to petrol. The slider lets you model your real mix.
- Does this include tax, insurance and servicing?
- No. This compares fuel and electricity only. EVs often win further on servicing and, for now, on some running taxes, while petrol cars can be cheaper to buy. For a full picture you would add purchase price, insurance, maintenance and depreciation.
- What about the EV per-mile tax from 2028?
- The government has signalled a per-mile charge for electric cars from around 2028. It is not in force yet and the detail may change, so we do not include it. When it lands it will add a small amount per mile to the EV side; you can factor it in once the rate is confirmed.
- How do you convert mpg to a cost?
- We turn your annual miles and mpg into litres using the UK gallon (4.54609 litres), then multiply by the pump price. The EV side converts miles into kWh using your efficiency, adds charging losses, and multiplies by your blended electricity rate.
Keep reading
Default rates and assumptions as of October 2026. These are typical figures to get you started, not quotes. Every value is editable, so change them to your own tariff, car and driving for a result that fits you.