Working out an electric car’s “fuel” cost is simpler than it first appears. Once you understand the terminology, the calculation is straightforward.
kWh (kilowatt-hour) is the unit used to measure electrical energy. As a simple comparison, think of it like the EV equivalent of a litre of fuel.
Battery capacity tells you the size of the car’s energy “tank”. In this example, the battery capacity is 105.2 kWh.
Electricity price is what you pay for each kWh. This varies depending on whether you charge at home, use a cheaper overnight tariff or use a public rapid charger.
Battery capacity × electricity price = approximate cost of a full charge
| Charging price | Calculation | Full-charge cost |
|---|---|---|
| 7p per kWh | 105.2 × £0.07 | £7.36 |
| 30p per kWh | 105.2 × £0.30 | £31.56 |
| 79p per kWh | 105.2 × £0.79 | £83.11 |
These prices are examples rather than tariff quotes. Simply replace them with the price shown on your home-energy tariff or public charger.
Divide the charging cost by the number of miles driven:
Charging cost ÷ miles driven = cost per mile
If a £31.56 charge gives you 350 miles, the calculation is £31.56 ÷ 350. That works out at approximately 9p per mile.
The battery size tells you how much energy the car can store. Multiply that figure by the price per kWh and you have a straightforward estimate of the cost of a full charge.
Thinking of changing to an electric vehicle? Sabre Motor Company can help you compare the vehicle, range and funding options so you can make an informed decision.
Figures are illustrative. Actual charging costs and vehicle range will vary by tariff, charger, charging losses, weather, driving conditions and individual vehicle efficiency.
About the author
Nathan Berry, Director of Sabre Motor Company, has more than 30 years of experience in the motor industry. Nathan and the Sabre team take a consultative approach, helping customers understand vehicle and funding options so they can make an informed decision.