A microwave draws about 1500 watts from the wall, or 1.50 kWh per hour. Enter your hours and electricity rate below for the exact cost per day, month and year.
Wattage is pre-filled with a typical value for a microwave; change any field for your own device, usage and rate. Cost uses your rate × kWh — a US-average placeholder rate of $0.17/kWh is shown; enter your own from your bill for an accurate figure.
A microwave draws about 1500 watts while running. Energy is billed in kilowatt-hours (kWh), and one kWh is 1000 watts for one hour — so a microwave uses 1500 ÷ 1000 = 1.50 kWh for every hour it is on. Multiply that by the hours you use it and by your rate per kWh to get the cost. The calculator above does it live; change the wattage if your model differs. Kept up every day of the year at 0.5 hours a day, that is about 274 kWh — roughly $46.54 at the $0.17/kWh placeholder rate used here.
High wattage but short bursts, so the daily cost is small.
Wattage moves with size, age and model, so treat 1500 W as a mid-range starting point rather than a fixed number. The power on the door or box is cooking output, not what the oven draws: GE's GCST11N1WSS, for example, is rated 950 W of cooking power but 1580 W electrical input. The rating plate on your own appliance, or its ENERGY STAR listing, gives the figure to type in. The rate matters just as much: the US Energy Information Administration publishes current average residential prices by state, and the figure on your own bill is better still. This LK Forge calculator recomputes every result as you type.
Two levers change the bill: hours of use and your rate per kWh. Running high-wattage devices less, or shifting them to off-peak hours on a time-of-use plan, has the biggest effect. For a whole-home estimate or to compare devices, use the full electricity bill & appliance calculator.