Home energy · EV charging
How long will the EV take to charge?
Battery kWh, start and target level, charger power. The result adds charging losses and shows the same charge at other common speeds.
Inputs
Starting values are illustrative, not current prices or specifications. Replace each with your own.
Result
Answer
Charging time in hours is the energy you add divided by the charger power, plus a loss allowance. Energy added is battery size times the change in charge level; because some energy is lost as heat, the supply delivers more than the battery receives.
Worked example
A 75 kWh battery charged from 10% to 80% adds 75 × 0.70 = 52.5 kWh. At 90% efficiency the supply delivers 52.5 ÷ 0.90 = 58.33 kWh. On a 7.2 kW charger that takes 58.33 ÷ 7.2 = 8.10 hours, or 8 h 6 min. The same charge on a 120 V cord at 1.44 kW takes 40.5 hours.
Formulas and notes
- Energy added = battery kWh × (target % − start %) ÷ 100.
- Energy from supply = energy added ÷ efficiency.
- Time = energy from supply ÷ charger kW (the lower of the charger and the car's limit, if you enter one).
- This uses a constant power. DC fast charging slows as the battery fills, so use the DC fast charging cost calculator with an average power for those sessions.
- Level 1 is 120 V; the 1.44 kW row is 12 A × 120 V. AFDC quotes about 1.9 kW for a typical Level 1 example. Level 1 charging needs a power outlet on a dedicated branch circuit (AFDC). Do not use extension cords or adapters for sustained charging, and have a licensed electrician check the outlet if you are unsure.
Planning estimate only, not professional advice. Sources, checked 2026-10-08: U.S. DOE Alternative Fuels Data Center, Electric Vehicle Charging Stations · U.S. DOE Alternative Fuels Data Center, Charging Electric Vehicles at Home
FAQ
How do you calculate EV charging time?
Divide the energy you need by the charger power. Energy is battery size times the percentage you are adding, and a loss allowance (this page assumes 90 percent efficiency unless you change it) raises the energy drawn from the supply.
Why is my real charging time longer than the result?
The result assumes constant power. Charging power can fall as the battery fills, the car may accept less than the charger offers, and cold batteries charge more slowly. Enter a lower efficiency or an onboard limit to approximate your case.
What kW should I enter for my charger?
Enter the supply power, which is amps times volts divided by 1,000. A 32 A circuit at 240 V is 7.68 kW; a 12 A cord on 120 V is 1.44 kW. If your car limits AC charging, put that limit in the optional field.
Is it better to charge to 80 percent or 100 percent?
This calculator only gives time for the range you pick. AFDC notes charging time depends on the starting charge level and battery capacity; follow your vehicle manual for the level it recommends for daily charging.
Does this work for DC fast charging?
Only roughly. DC fast chargers deliver varying power during a session, so enter an average power for that session, ideally from your own past charges.