How Much Does It Cost to Run a Microwave?

A microwave's advertised power, such as 800 W or 1,200 W, is its cooking output. It draws more from the socket: Samsung's 800 W MS23K3513AK is rated at 1,150 W on 230 V, and Panasonic's 1,200 W NN-SN686S at 1,480 W on 120 V.

We use 1,200 W as a typical input. Five minutes at full power uses 0.1 kWh, and a 2-minute reheat uses 0.04 kWh.

At 15 minutes a day that's 0.3 kWh: about $0.05 a day in the US, £0.08 in the UK and €0.11 in Germany. Over a month it comes to about 9 kWh, or $1.66, £2.40 and €3.30.

On a lower power setting, most microwaves switch the magnetron fully on and off in cycles: at 50% power it runs about half the time. Inverter models lower the power steadily instead.

Either way, the energy depends on how long the magnetron actually runs. Half power for twice as long uses about the same energy as full power.

The clock and controls draw a little power around the clock. Under Canadian rules, new microwave-only and countertop convection models may use no more than 1.0 W in standby, falling to 0.6 W for models made from 22 June 2026.

At 1 W, standby adds about 9 kWh a year, close to a month of our typical cooking use.

For reheating and small portions, a microwave usually uses less energy than an electric oven, which has to heat a large insulated box and the air inside before it heats the food.

For large dishes that fill the oven, the gap narrows.

For boiling water, an electric kettle is usually more efficient. It heats the water directly and switches off at the boil.

At 15 minutes a day, a microwave uses about 110 kWh a year, roughly what a typical fridge-freezer uses in three months.

The power in a microwave's name is its cooking output. The input power on the rating plate, usually inside the door or on the back, is what you pay for; use that figure in the calculator.

• Use the microwave instead of the oven for reheating and small portions.
• Cover food so it heats faster and more evenly.
• Cut food into even pieces and stir halfway, so it doesn't need extra time.
• Boil water in a kettle rather than the microwave.
• Defrost food in the fridge overnight when you can plan ahead.
• If you don't need the clock, switching off at the wall saves the standby power, though on a new model that's only about 1 W.

• Refrigerator
• Electric kettle
• Rice cooker
• Air fryer
• Bill analyzer