EV Charging Time Calculator

How this calculator works

Energy needed = battery capacity × (target % − starting %). Charging time = energy needed ÷ charger power.

For Level 1 and Level 2 (AC) charging, about 10% of the power is lost in the car’s onboard charger, so the calculator uses 90% of the charger’s power. A Level 2 charger on a 40 A circuit can deliver 32 A, or about 7.7 kW at 240 V; the options shown are common charger ratings.

DC fast chargers slow down as the battery fills, especially above about 80%, and the car may accept less than the charger’s maximum. Treat the DC result as a best case.

Example: a 75 kWh battery from 20% to 80% on a 7.2 kW Level 2 charger

1. Energy: 75 × 60% = 45 kWh.
2. Time: 45 ÷ (7.2 × 0.9) = 6.9 hours, about 6 h 57 min.

Tips before you buy

• Level 1 is fine if you drive under about 40 miles a day and can plug in for 10+ hours overnight.
• Check the car’s onboard charger limit — many EVs accept 7.2 to 11.5 kW on Level 2, so a bigger charger may not be faster.
• Use the watts to amps calculator to see the circuit a Level 2 charger needs.