EV Charging Time Calculator
Enter battery capacity, start and target percentages and charger power to see the ideal time, assuming the charger delivers that power the whole way.
How it works
Energy to add is capacity × (target % − start %) ÷ 100. Ideal time is that energy divided by charger kilowatts. 36 kWh at 7.2 kW is 5 hours. Real charging is often slower: AC efficiency losses, cabin preconditioning, and especially DC fast charging, which reduces power as the battery fills. Treat this as a best-case planning number, not a stopwatch.
Formula
Energy (kWh) = capacity × (target % − start %) ÷ 100 Hours = energy ÷ charger kW
Worked examples
- 60 kWh, 20% → 80%, 7.2 kW → 36 kWh, 5 hours
- 50 kWh, 40% → 40%, 11 kW → 0 hours
Useful notes
- Assumes constant charger power. DC fast charging tapers near the top of the pack.
- This is time, not cost. Use EV Charging Cost for the bill.
FAQ
- Why is my real charge slower than this?
- Power is not constant. Fast chargers taper, cold batteries accept less current, and some of the meter’s energy is lost as heat.
- Should I use the car’s peak kW or the station’s?
- Use the lower of the two. A 150 kW stall cannot push 150 kW into a car whose onboard limit is 50 kW.
- Does this include charging losses?
- No. It divides battery energy by charger kW. Losses make grid energy higher and can stretch clock time slightly on AC.
Related tools
See all Energy tools.