Estimate what it costs to charge your electric car at home or in public, see the cost per 100 miles,
and compare it against running a petrol car. Adjust the inputs below for your own EV and tariff.
How EV charging costs are calculated
Charging cost depends on the energy drawn from the charger (kWh) and your rate (p/kWh). Energy added to
the battery is its capacity multiplied by the percentage gained. The calculator divides that battery energy
by an assumed efficiency factor of 0.9 to estimate charger energy, allowing for 10% charging losses.
Multiply the estimated charger energy by your rate to get the cost. For public charging,
select a checked network tariff or enter the rate shown at your charger.
For a fair comparison with petrol, this calculator converts everything to cost per 100 miles using your car's
efficiency in miles per kWh. The petrol comparison uses example assumptions of 45 UK mpg and 174.88p per litre.
Change the fuel price and petrol efficiency inputs to match your car and local pump price. For a full network
price breakdown, see our EV charging costs guide, and check our
free EV charging guide for ways to charge for nothing. To see how long a charge takes, use the EV charging time calculator, and for how far a charge goes, the EV range calculator.
EV vs petrol: cost per mile and running cost
An EV at 3.6 mi/kWh with 10% charging losses costs 2.0p a mile on a 6.5p/kWh off-peak home rate.
The same EV costs 8.1p a mile on a 26.32p/kWh standard home rate.
The example petrol car at 45 UK mpg and 174.88p a litre costs 17.7p a mile.
Over 8,000 miles a year (an example mileage) the off-peak EV costs £160.
The standard-rate EV costs £650.
The petrol car costs £1,413.
Enter your own rate and mileage in the calculator for your figure.
Example costs per charge
These figures use the same sums as the calculator, for a 20% to 80% charge with 10% charging losses.
Pick your own battery and rate in the tool above.
Cost of a 20% to 80% charge, including 10% charging losses. Octopus, Ofgem and Zapmap rates checked 2 November 2026; your own tariff may differ.
| Battery | Energy drawn | Home off-peak (6.5p/kWh) | Ofgem cap (26.32p/kWh) | Rapid average (79p/kWh) |
| 40kWh | 26.7kWh | £1.73 | £7.02 | £21.07 |
| 60kWh | 40.0kWh | £2.60 | £10.53 | £31.60 |
| 80kWh | 53.3kWh | £3.47 | £14.04 | £42.13 |
Sources:
Intelligent Octopus Go off-peak rate, 11:30pm to 5:30am, as shown on the Octopus Energy page (checked 2 November 2026); Ofgem price cap, Direct Debit average, 1 October to 31 December 2026 (checked 1 November 2026); Zapmap Price Index, September 2026, pay-as-you-go rapid and ultra-rapid (50kW and above), updated 7 October 2026 (checked 1 November 2026).
Public rapid prices vary by network, so check the price shown at the charger. For a network-by-network breakdown, see the EV charging costs guide.