kWh (kilowatt-hour)
Kilowatt-hour
The unit of energy used for battery capacity and electricity billing. Think of kWh as the size of an electric car's tank.
A kilowatt-hour (kWh) is a unit of energy: the amount delivered by one kilowatt of power flowing for one hour. For electric cars it plays the role the fuel tank's liters play for a gas car; the Australian Government makes the same comparison, noting that battery capacity in kWh is similar to a fuel tank's capacity. A battery's usable capacity in kWh, divided by the car's consumption, gives a range estimate: the EPA's example is 100 kWh of usable capacity at two miles per kWh, or 200 miles.
Electricity is metered in kWh, as the US Energy Information Administration explains, which makes charging cost easy to estimate: multiply the energy you add by your home tariff or the charging network's price. This is the arithmetic behind CarPairly's cost tools.
Do not confuse kWh with kW. Kilowatts measure power, how fast energy flows, so motor output and charging speed are quoted in kW, while the battery that stores the energy is quoted in kWh. When a spec sheet lists two battery figures, the smaller, usable one is the number that determines range.