Kilowatt-Hour

A kilowatt-hour (kWh) is a unit of energy equal to one kilowatt of power used for one hour. EV battery sizes, electricity bills and the EPA's kWh per 100 miles ratings are all measured in kWh.

Charging time is kWh divided by kilowatts. A 20% to 80% charge on a 75 kWh battery puts 45 kWh in, or about 50 kWh from the wall at 90% efficiency. On a 7.7 kW charger that takes 6 hours 31 minutes. The EV charging time calculator runs this for any battery.

Cost uses the same number. At 18 cents per kWh, 50 kWh costs $9.00. The EV charging cost calculator applies your own rate, and 1 kWh equals 1,000 watt-hours.