How much does it cost to charge an EV?
Divide the energy added to the battery by charging efficiency to estimate electricity drawn from the grid, then multiply by the applicable price per kilowatt-hour and add any session fee.
Add 50 kWh at 90% efficiency
55.56 kWh drawn from the grid
The charging-cost calculation
Charging efficiency accounts for conversion, heat, battery conditioning, and vehicle-system losses. Use session energy from the charger or vehicle when it is available.
Use the right electricity price
Home rates can vary by utility, season, and time of use. Public chargers may price by kilowatt-hour, time, session, or subscription and may add idle or parking fees. Your bill’s effective average price can also differ from the energy-only rate because of fixed charges.
EIA publishes state average retail electricity prices, but it explains that those averages are not the tariff applied to an individual customer. Use your current utility plan for a personal estimate.
Cost per mile
If the vehicle uses 30 kWh from the battery per 100 miles and charging is 90% efficient, the grid supplies about 33.33 kWh per 100 miles. At $0.18/kWh, electricity costs about $6.00 per 100 miles, or 6 cents per mile.
What changes the result?
- Energy actually added to the battery.
- Charging efficiency and battery temperature.
- Home, workplace, or public charging price.
- Time-of-use and demand pricing.
- Session, parking, subscription, or idle fees.
- Energy used for cabin or battery conditioning while connected.
Frequently asked questions
Is battery capacity the same as energy used in a session?
No. A session usually adds only part of the battery’s usable capacity. Use the actual energy added when possible.
Does charger power change the energy cost?
Power changes charging speed. It can also affect efficiency and pricing, especially at public fast chargers, but cost still depends on energy and the pricing structure.
Where can I find kWh per 100 miles?
Check the vehicle’s efficiency display, manufacturer information, or FuelEconomy.gov for comparable standardized values.