A kilowatt-hour measures the energy capacity of an electric vehicle’s battery pack.
A kilowatt-hour, abbreviated kWh, is a unit of energy equal to one kilowatt delivered for one hour. Electric-vehicle manufacturers use it to describe how much electrical energy a battery can store. A larger kWh rating generally allows a vehicle to travel farther, although weight, speed, temperature, aerodynamics, and driving conditions also matter.
Kilowatts measure power, not stored energy. A battery’s maximum charging or motor output may be stated in kilowatts, while its stored capacity is stated in kilowatt-hours. Volts describe electrical potential, and amperes describe electric current, so neither is a direct measure of battery capacity.
Usable capacity can be lower than a battery’s gross capacity because manufacturers often reserve energy at the top and bottom of the pack to reduce degradation. For that reason, two vehicles with similar kWh ratings can have different driving ranges and charging behaviour.