Appliance Cost Lab

Microwave guide

How much electricity does a microwave use?

Use electrical input watts—not marketed cooking output—multiplied by minutes per use, uses per week and any evidence-based duty cycle.

Minutes belong in the minutes field. Short heating times should not be converted into awkward decimal hours. The calculator converts minutes with ÷ 60.

Three reproducible use scenarios

Three published microwave electricity-cost scenarios
Scenario Inputs Active per use Annual energy Annual cost
1,200 W for three minutes, five uses per week 1,200 W input; 3 min/use; 5 uses/week; 100% duty; 2 W standby; $0.18/kWh 0.060 kWh/use · $0.01/use 33.163 kWh $5.97
1,500 W for five minutes, seven uses per week 1,500 W input; 5 min/use; 7 uses/week; 100% duty; 2 W standby; $0.18/kWh 0.125 kWh/use · $0.02/use 63.145 kWh $11.37
1,700 W for ten minutes, fourteen uses per week at 80% duty 1,700 W input; 10 min/use; 14 uses/week; 80% duty; 2 W standby; $0.18/kWh 0.227 kWh/use · $0.04/use 182.987 kWh $32.94

$0.18/kWh is an illustrative comparison rate, not a national or current market price. Cost per use excludes the separately calculated clock/display standby.

Input and measurement traps

Cooking output describes energy delivered to food; it is not necessarily wall-plug electrical input. Look for electrical input on the rating plate or instructions. Lower power settings may cycle the magnetron, so duty cycle applies only when supported by the selected mode or a representative measurement.

Measure clocks and displays separately. A complete cooking-use kWh measurement should cover the representative heating interval, while annual standby remains a separate entry.

Safety and disconnection

Smart-plug control is blocked. Any disconnection decision must account for clock and settings loss, manufacturer instructions, electrical ratings and safe operation. Follow the manual, especially if the door, seals or interlocks are damaged.
Sources: USDA microwave guidance supports the cooking-power cycling distinction; FDA microwave safety guidance supports following instructions and damage warnings. Neither validates these inputs.

Open the microwave minutes-per-use calculator

Related: microwave versus electric-oven comparison · air-fryer guide · dishwasher guide · methodology · accuracy · sources · standby power

Last reviewed: August 14, 2026