SnapEnergyLab

Appliance running costs

How many watts does a microwave use?

A household microwave typically draws roughly 900 W to 1,800 W from the wall while it is running. That input power is higher than the cooking power printed on the front — a 1,000–1,100 W microwave commonly draws around 1,300–1,500 W. Because it only runs for minutes at a time, its daily energy use is small.

How many watts does a microwave use?

Example: a 1,400 W microwave used 5 minutes, 2 times a day uses 0.233 kWh per day, about 7.10 kWh per average month and 85.2 kWh per year. At $0.180/kWh that is $0.04 per day, $1.28 per month and $15.34 per year. The 1,400 W is an example, not a figure for every microwave — enter your own below.

Use 'input power' or 'power consumption' from the label — not the cooking-power headline.

$0.021

per use

0.117 kWh per use · 10.0 minutes a day in total

Calculated from your inputs
kWh per month
7.10 kWh
Cost per month
$1.28
kWh per year
85.2 kWh
Cost per year
$15.34

Method

  1. hours per use = minutes per use ÷ 60
  2. kWh per use = input watts ÷ 1,000 × hours per use
  3. cost per use = kWh per use × rate
  4. kWh per month = kWh per use × uses per day × 30.44 days
  5. kWh per year = kWh per use × uses per day × 365.24 days

Assumptions

  • Input (wall) watts drawn while heating, at 100% of the minutes entered.
  • No standby or clock-display draw is added.
  • Average month 30.44 days; average year 365.24 days.

What can change the result?

  • Input power versus advertised cooking output
  • Minutes per use
  • Number of uses per day
  • Power level, which on many models changes on-time rather than wattage

Typical microwave wattage — and what the number means

What the figure represents: Input power (power consumption) drawn from the outlet while heating — not the advertised cooking output wattage.

Rated or typical power is what a label or spec sheet lists. Your watts is the value you enter in the calculator. Actual energy use (kWh) is watts × time — which is why the same microwave can cost very different amounts in different homes.

Illustrative bands to orient you, not measured averages. Use your own model's figure where you can.
TypeApproximate powerNote
Compact (≈700 W cooking)about 1,000–1,200 W inputIllustrative range
Mid-size (≈1,000–1,100 W cooking)about 1,300–1,500 W inputExample: 1,100 W cooking / 1,440 W consumption on one manufacturer spec
Large / over-the-range (≈1,200 W+ cooking)about 1,500–1,800 W inputIllustrative range

What changes how much electricity a microwave uses

  • Input vs output: the cooking-power headline understates what the oven draws from the wall.
  • Minutes per use and uses per day set the energy — microwaves are short-duration loads.
  • Power level: on many models lower settings cycle full power on and off rather than reducing watts.

A microwave has two wattage figures. The large number on the front or the box is usually cooking output — the microwave energy delivered to the food. The electricity drawn from the wall (input power or power consumption) is higher, because the magnetron, transformer, fan, turntable and light all have losses. For electricity use and cost, the input figure is the one that matters.

Look for 'input power', 'power consumption' or 'rated input' on the label inside the door or on the back — not the cooking-power headline. Running at a lower power level does not mean a lower wattage for most microwaves: many cycle the magnetron on and off at full power instead.

Electricity use at different usage patterns

All rows use 1,400 W at $0.180/kWh, with no standby added. Only the usage changes.

Generated by the same energy engine that powers the calculator above.
UsagekWh per dayPer dayPer monthPer year
2 min, once a day0.047 kWh$0.01$0.26$3.07
5 min, twice a day0.233 kWh$0.04$1.28$15.34
5 min, four times a day0.467 kWh$0.08$2.56$30.68
10 min, three times a day0.700 kWh$0.13$3.84$46.02

Electricity use across the wattage range

From 900 W to 1,800 W, each used 5 minutes, 2 times a day.

Same engine, same rate; only the wattage changes.
PowerkWh per dayPer dayPer monthPer year
900 W0.150 kWh$0.03$0.82$9.86
1,400 W0.233 kWh$0.04$1.28$15.34
1,800 W0.300 kWh$0.05$1.64$19.72

Where these numbers come from

  • Manufacturer specifications list both cooking power and power consumption; one example over-the-range model lists 1,100 W microwave power and 1,440 W power consumption.
  • The 1,400 W default is a SnapEnergyLab example of input power for a mid-size microwave, not a measured average.

Worth knowing

Clock and display standby draw is not included in the figures on this page.

Worth knowing

Using the cooking-output wattage instead of input wattage underestimates electricity use.

Your next decision

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Defaults come from the published default registry and the formulas are documented in the methodology.