Can I run a microwave on a 15-amp circuit?

Yes. At about 8.3 A it stays under the 12 A continuous limit (80% of 15 A) that applies to a 15 A breaker, leaving room on the circuit.

What size breaker does a microwave need?

Guidance for a dedicated circuit is a 15 A breaker with 14 AWG copper wire (75°C terminations). Always size from the nameplate and confirm with a licensed electrician: conductor length, ambient temperature, and local code change the answer.

How many watts does a microwave use?

Microwave typically draws about 1,000 running watts. See what that costs on our cost-to-run page, or use the wattage chart for other appliances.

Does a microwave need a dedicated 20-amp circuit?

A dedicated 20 A circuit is the usual requirement for a built-in or over-the-range microwave, and most manufacturers specify it. At 8.3 A a microwave is close enough to a 15 A breaker's limit that sharing it with other kitchen loads causes nuisance trips. A countertop unit on an existing kitchen receptacle is a different case. Follow the nameplate and your local code.

Why is my microwave's wattage different from what the box said?

The box advertises cooking power, which is how much energy reaches the food. The plate on the appliance lists input power, which is what the circuit supplies. The oven is not 100% efficient, so input is always higher than output. Breaker and generator sizing uses the input figure.

Can a microwave and a refrigerator share a circuit?

It is a bad idea even where code permits it. The microwave's 8.3 A is a heavy intermittent load, and a trip takes the fridge down with it, often unnoticed until the food has warmed. Kitchens are the one room where dedicated circuits earn their cost.

How Many Amps Does a Microwave Use?

Microwave draws about 8.3 amps at 120 volts (1,000 watts running). At 8.3 A, a microwave fits comfortably on a standard 15 A or 20 A household circuit (kitchen countertop receptacles are on 20 A small-appliance circuits per NEC 210.11(C)).

Power (watts)

Voltage

Amps = watts ÷ volts. Enter the wattage from your appliance's nameplate or label for an exact figure.

Current draw: a microwave

8.3 A

At 120 V: 1,000 W
Typical breaker: 15 A

Breaker figure is guidance for a simple resistive load; confirm against the nameplate and a licensed electrician.

Microwave amperage at 120 V and 240 V

Same 1,000 W load: the current halves when the voltage doubles. Microwave is typically a 120 V appliance in US homes.

Draw	Watts	Amps at 120 V	Amps at 240 V
Running	1,000 W	8.3 A	4.2 A

Microwaves are sold by cooking power, the "1,000-watt microwave" on the box, while the plate on the back lists the input power the oven actually pulls from the wall. Those are different numbers, and the input is the higher of the two. Use the ladder below with the figure from the plate, not the one on the box.

Microwave amps by input wattage

Read the input watts from the plate on the back or inside the door frame, then read across. The advertised cooking power will be lower than this.

Rated watts	Amps at 120 V	Fans per 15 A circuit
700 W	5.8 A	2
1000 W (typical)	8.3 A	1
1200 W	10 A	1
1500 W	13 A	0
1800 W	15 A	0

Per-circuit counts use the 12 A continuous limit (80% of a 15 A breaker) and assume nothing else is on the circuit.

How long a microwave runs on a power station

A microwave is a short, heavy load rather than a long one. What matters is whether the inverter can deliver the draw at all: minutes of runtime are rarely the constraint. Based on a 1,000 W load and 85% inverter efficiency.

Battery capacity	Approx. runtime
300 Wh	0.3 hours
500 Wh	0.4 hours
1,000 Wh	0.9 hours
2,000 Wh	1.7 hours

See how to size a portable power station for how to size one, or the power station picks for units at each capacity.

Breaker and circuit for a microwave

At 8.3 A, a microwave fits comfortably on a standard 15 A or 20 A household circuit (kitchen countertop receptacles are on 20 A small-appliance circuits per NEC 210.11(C)). For a dedicated circuit, guidance is a 15 A breaker with 14 AWG copper (75°C terminations).

Guidance only: actual circuit sizing depends on your unit's nameplate, wire run length, and local code. Confirm with a licensed electrician. See the wire & breaker size chart for the full NEC ampacity table.

Measure what a microwave actually draws

The figures above are typical ratings. A plug-in power meter between the outlet and the cord shows the real amps and watts with nothing opened up. A clamp meter reads one conductor at a time, so it is the tool for hardwired and 240 V circuits; clamped around a whole cord it reads close to zero.

We earn a commission if you buy through links on this page, at no extra cost to you. It does not change what we recommend. See our affiliate disclosure. As an Amazon Associate I earn from qualifying purchases.

Plug-in power meter

P3 International Kill A Watt P4400

Best for: Measuring what one plug-in appliance really uses

Check price at P3 International

Clamp meter

Fluke 323

Best for: Measuring what a hardwired circuit actually draws, even in a crowded panel

Check price on Amazon(paid link)

Energy meter and monitor picks

Frequently asked questions

Microwave typically draws about 8.3 amps at 120 volts, based on a typical rating of 1,000 watts (amps = watts ÷ volts). Check the nameplate on your specific unit: ratings vary by model.

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How Many Amps Does a Microwave Use?

Microwave amperage at 120 V and 240 V

Microwave amps by input wattage

How long a microwave runs on a power station

Breaker and circuit for a microwave

Measure what a microwave actually draws

P3 International Kill A Watt P4400

Fluke 323

Frequently asked questions