Electric car vs petrol: running costs
Compare the cost of fuelling an electric car with a petrol or diesel one, for the miles you drive.
Electricity: Ofgem's price cap for 1 October to 31 December 2026. Fuel: average UK pump prices for the week beginning 9 November 2026.
Result
Over 8,000 miles a year, the electric car costs £778 less to fuel than the petrol car, with electricity at the price cap rate of 26.32p per kWh and petrol at this week's UK average of 170.71p a litre.
a year less for the electric car, to the nearest pound
| Electric car, a mile | 7.5p |
|---|---|
| Petrol car, a mile | 17.2p |
Fuel and electricity only. Buying, insuring, taxing and servicing the cars are left out.
Show the workings
| Step | Sum | Answer |
|---|---|---|
| Electric car: cost of one mile | 26.32p per kWh ÷ 3.5 miles per kWh | 7.5p |
| Electric car: a year | 7.5p × 8,000 miles | £601.60 |
| Petrol car: litres for one mile | 4.54609 litres in a gallon ÷ 45 miles per gallon | 0.101 litres |
| Petrol car: cost of one mile | 0.101 litres × 170.71p per litre | 17.2p |
| Petrol car: a year | 17.2p × 8,000 miles | £1,380 |
| Difference over a year | £1,380 − £601.60 | £778.07 |
What this leaves out or assumes
- This compares fuel and electricity only. Buying, insuring, taxing and servicing the cars are left out.
- Miles per kWh and miles per gallon change with speed, weather and how you drive.
- Charging losses are left out. Some electricity turns to heat between the socket and the battery.
- Miles per gallon means the UK gallon. American figures use a smaller gallon and are not comparable.
Where the figures come from
- Electricity unit rate, price cap, Great Britain average, Direct Debit: 26.32p per kWh. Source: Ofgem: Energy price cap unit rates and standing charges. Checked 13 November 2026.
- Average UK pump price of unleaded petrol: 170.71p a litre. Source: DESNZ: Weekly road fuel prices. Checked 13 November 2026.
- One UK gallon, in litres: 4.54609 litres. Source: Weights and Measures Act 1985, Schedule 1. Checked 13 November 2026.
Cost per mile: petrol and diesel
At this week's average pump prices: 170.71p a litre for petrol and 198.19p for diesel.
| Fuel economy | Petrol, a mile | Diesel, a mile |
|---|---|---|
| 30 mpg | 25.9p | 30p |
| 40 mpg | 19.4p | 22.5p |
| 50 mpg | 15.5p | 18p |
| 60 mpg | 12.9p | 15p |
Cost per mile: electric
At the price cap rate of 26.32p per kWh, the average for Great Britain when paying by Direct Debit.
| Efficiency | A mile | 100 miles |
|---|---|---|
| 2.5 miles per kWh | 10.5p | £10.53 |
| 3 miles per kWh | 8.8p | £8.77 |
| 3.5 miles per kWh | 7.5p | £7.52 |
| 4 miles per kWh | 6.6p | £6.58 |
| 4.5 miles per kWh | 5.8p | £5.85 |
Charging at home on a tariff with a cheap overnight rate costs less than this. Public rapid chargers usually cost more. Choose "My own rate" in the calculator to use your price.
How the sum works
For the electric car, divide the price of a kWh by the miles the car travels on one. For petrol or diesel, divide the litres in a gallon by the car's miles per gallon to get the litres it burns in a mile, then multiply by the price of a litre. A UK gallon is 4.54609 litres.
This compares fuel and electricity only. The price of the car, insurance, tax, servicing and tyres all differ too.
Pump prices: DESNZ: Weekly road fuel prices, week beginning 9 November 2026. Electricity: Ofgem: Energy price cap unit rates and standing charges. Checked 13 November 2026.