EV Charging Cost Calculator
Estimate the grid energy and electricity cost required to add a chosen amount of energy to an EV battery.
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How this calculator works
Grid energy = battery energy added ÷ charging efficiency. Cost = grid energy × electricity rate + session fee.
Worked example
Adding 50 kWh at 90% efficiency requires about 55.56 kWh from the grid and costs about $8.89 at $0.16/kWh.
Distinguish battery energy from grid energy
If the battery gains 40 kWh, the wall usually supplies more than 40 kWh because charging has losses. The efficiency input converts desired battery energy into estimated grid energy. Use measured charger consumption when available for a vehicle- and climate-specific result.
Charging speed changes time but does not directly set the electricity price. Utility rates, time-of-use periods, demand charges, session fees, and taxes can change the actual bill.
Compare charging scenarios fairly
Use the same added battery energy when comparing home and public charging. Enter the marginal electricity rate that applies during the charging window, not an unrelated average bill rate. For trip planning, include the network’s per-kWh or per-minute fee and any idle or parking charges separately.
Sources & assumptions
Grid energy is battery energy divided by charging efficiency. The U.S. Department of Energy notes that charging involves energy loss; actual efficiency varies by charger, vehicle, temperature, and battery conditioning. See DOE charging-loss data.
Frequently asked questions
Why is grid energy higher than battery energy?
Charging loses some energy as heat and through power conversion, battery conditioning, and vehicle systems.
Where do I find my electricity rate?
Use the energy charge from your utility bill and account for time-of-use pricing or public-charger fees when applicable.