Cooking on full power, the microwave uses 1100 watts of electricity per hour. That equates to 1.1 kilowatts per hour. Kilowatt hour usage and cost per kwh is how electricity is priced.
A rate of 10 cents per kwh equals 11 cents per hour to operate an 1100-watt microwave.
Watt usage from a microwave can be significantly less than its rating if lower power settings are used. For example, cooking on a power setting of five generally means a 50 percent reduction in energy usage. Watt measuring devices, such as Kill A Watt, can be used to calculate electrical usage on microwaves or other 120-volt appliances when the wattage is unknown.