EV Charging Time Calculator
Estimate charging time from your battery size, the charge you want to add and the charger's power. This is a simple constant-power estimate.
How it works
Energy added = battery capacity × (target % − start %) ÷ 100. Charging time (hours) = energy added ÷ (charging power × efficiency), where charging power is the lower of the charger's rating and your car's maximum rate if you enter one.
Worked example: A 60 kWh battery charged from 0% to 50% adds 30 kWh. On a 7.2 kW charger at 90% efficiency: 30 ÷ (7.2 × 0.90) = 4.63 hours, or 4 h 38 min.
Assumptions
- Constant charging power the whole session. Real sessions taper as the battery fills; U.S. DOT notes DC fast charging to 80% takes roughly 20 minutes to 1 hour, and the last portion is slower.
- The 90% charging efficiency is an editable placeholder assumption, not an official figure. Set it to 100 to see the ideal time.
- Battery capacity should be usable capacity if you know it; battery temperature and age are not modeled.
- Charger power is the power actually delivered. Many home chargers deliver less than their maximum depending on the circuit.
Frequently asked questions
How many kW is a typical home charger?
The U.S. DOE Alternative Fuels Data Center says most residential Level 2 chargers operate at up to 30 amps, delivering 7.2 kW, and a Level 2 unit can range from 2.9 to 19.2 kW.
Why is my real charging time longer?
DOE notes charging time depends on the battery's state of charge, its capacity, the vehicle's internal charger capacity and the charging equipment. DOT adds that charging slows as the battery nears full.
Related calculators
- EV charging cost calculator
- EV charger power and miles-per-hour calculator
- MPGe, kWh/100 mi and miles/kWh converter
- Gas vs electric cost per mile
- Cost to charge an EV battery from X% to Y%
- Per-kWh vs per-minute charging price
- kW to kWh calculator
- EV charger amps to kW chart
Sources
Formulas and reference values are from these sources. Page last reviewed 2026-10-19.