kW stands for kilowatt, which is a measure of power, while kWh stands for kilowatt-hour, which is a measure of energy. Power is the rate at which something uses energy, while energy is the capacity to do work. A kilowatt is simply a measure of how much power an electric appliance consumes, and its 1,000 watts to be exact. A kilowatt-hour is a composite unit of energy equal to one kilowatt sustained for one hour. It is equal to 3,600 kilojoules or 3.6 MJ. Kilowatt-hours are a common billing unit for electrical energy supplied by electric utilities. To calculate the kWh of an appliance, you need to estimate the amount of time you use it. Knowing the difference between kW and kWh is essential for monitoring and managing electricity consumption.