Home energy · EV charging
What does a fast charge really cost?
Enter the network's prices and your car's average charging power. Compare per-kWh and per-minute billing and your home rate.
Inputs
Starting values are illustrative, not current prices or specifications. Replace each with your own.
Result
Answer
Per-kWh billing costs energy times price. Per-minute billing costs session minutes times the per-minute price, so a car that charges slowly pays more per kWh. The two are equal at an average power of price per minute × 60 ÷ price per kWh.
Worked example
Adding 10% to 80% of a 75 kWh battery is 52.5 kWh. At an average 105 kW the session takes 30 minutes. Per-kWh billing at $0.55 costs 52.5 × 0.55 = $28.88. Per-minute billing at $0.40 costs 30 × 0.40 = $12.00, equal to $0.23 per kWh. The two prices break even at 0.40 × 60 ÷ 0.55 = 43.6 kW. At home, $0.12 per kWh would cost $6.30 for the same energy.
Formulas and notes
- Energy = battery kWh × (target % − start %) ÷ 100. Billed energy is assumed equal to energy into the battery; check your receipt.
- Minutes = energy ÷ average kW × 60.
- Per-kWh cost = energy × price + session fee. Per-minute cost = minutes × price + session fee.
- Break-even average power = price per minute × 60 ÷ price per kWh. Above it, per-minute is cheaper.
- Idle fees, parking charges, membership discounts and taxes are not modelled.
Planning estimate only, not professional advice. Sources, checked 2026-10-08: U.S. DOE Alternative Fuels Data Center, Electric Vehicle Charging Stations · Geotab, EV Battery Health: Key Findings from 22,700 Vehicle Data Analysis (Apr. 28, 2026)
FAQ
Is per-minute or per-kWh fast charging cheaper?
It depends on your average power. Per-minute billing is cheaper when your car charges faster than the break-even power the calculator shows, and costlier when it charges slowly, for example in the cold or near a full battery.
What average power should I enter?
Divide the kWh added by the hours of the session using a past charge. Do not use the peak figure from the spec sheet.
How long does a fast charge take?
AFDC says charging time can range from less than 20 minutes on DC fast chargers to 20 hours or more on Level 1, depending on state of charge, battery capacity and charger power. This calculator uses the average power you enter.
Why does fast charging cost more than home charging?
Public networks include equipment, demand charges, site costs and margin in their price. Enter your home rate to see the gap on the same energy.
Does frequent fast charging wear the battery?
Geotab's 2025 analysis found vehicles that DC fast charge on more than 12% of sessions, with over 40% of those sessions above 100 kW, averaged 3.0% a year, versus 1.5% for vehicles that DC fast charge on under 12% of sessions. See the battery degradation calculator.