How Many Amps Does a Microwave Use?

Microwaves are convenient cooking appliances that people use not only in their homes but also in RVs, boats, and various other places. Knowing how many amps a microwave uses helps ensure you don’t overload the electrical circuit, no matter where you plan to use it.

This guide will break down how many amps microwaves use, considering the different wattage levels they have and the various voltage standards around the world. We’ll also explain how to calculate amps so you can work out exactly how many your microwave uses.

Amps, volts, and watts explained

Before we start, below is a brief explanation of what amps, watts, and volts are for those who don’t already know. Having a basic knowledge of these will help you better understand everything else in this guide:

Amp: A unit of electric current.
Volt: A unit of electric potential (electrical pressure).
Watt: A unit of electric power.

To understand these, it helps to use the water pipe analogy.

Amps measure the volume of water (current of electrons) flowing through the pipe (circuit). Volts measure the pressure (potential) pushing the water (electricity) through the pipe (circuit). Watts measure the power of the water (electricity) flowing through the pipe (circuit), taking into consideration the volume (amps) and pressure (volts).

Calculating amps, volts, and watts

As long as you know two of the three electrical units, you can work out what the third one is.

Watts are simply amps times volts; amps are watts divided by volts; and volts are watts divided by amps.

So if you have a 1200-watt microwave running on a 120-volt supply, you have 10 amps flowing through the circuit. Here’s how to do the calculation:

10 amps x 120 volts = 1200 watts
1200 watts ÷ 120 volts = 10 amps
1200 watts ÷ 10 amps = 120 volts

How many amps do microwaves use?

How many amps a microwave uses depends on the wattage of the microwave and the voltage in your area. For instance, if you live in the USA or Canada, the power supply is 120 volts, meaning your microwave will use this many amps depending on its wattage:

600-watt microwaves use 5 amps (600 watts ÷ 120 volts)
700-watt microwaves use 5.83 amps
800-watt microwaves use 6.67 amps
900-watt microwaves use 7.5 amps
1000-watt microwaves use 8.33 amps
1200-watt microwaves use 10 amps
1500-watt microwaves use 12.5 amps
2000-watt microwaves use 16.67 amps

However, if you live in Europe, the United Kingdom, Australia, New Zealand, or another country that uses 230 volts, this is how many amps microwaves use:

600-watt microwaves use 2.61 Amps (600 watts ÷ 230 volts)
700-watt microwaves use 3.04 Amps
800-watt microwaves use 3.48 Amps
900-watt microwaves use 3.91 Amps
1000-watt microwaves use 4.35 Amps
1200-watt microwaves use 5.22 Amps
1500-watt microwaves use 6.52 Amps
2000-watt microwaves use 8.70 Amps

Efficiency of microwaves

The wattage of a microwave refers to the amount of power it uses to heat the food rather than the total amount the microwave consumes. You can think of it as its cooking power (output power) versus its power consumption (input power).

Since microwave ovens aren’t 100% efficient, on average, only around 60% (it ranges from 50% to 75%) of the electricity they consume is converted into the microwave radiation that’s used for cooking.

That means that microwaves actually use more watts than their stated wattage, and therefore, more amps too. This needs to be taken into consideration when planning electrical circuits and selecting circuit breakers for microwave ovens.

The actual amps and watts microwaves use

Based on a 60% efficiency, that would mean a 1200-watt microwave running on a 120-volt supply would actually consume around 2000 watts and draw 16.67 amps instead of 10 amps:

60% of 2000 watts is 1200 watts (1200 ÷ 0.6)
2000 watts ÷ 120 volts = 16.67 amps

If you have a 120-volt power supply, this is how many watts and amps microwaves may actually use if they’re 60% efficient:

A 600-watt microwave would use 1000 watts and 8.33 amps.
A 700-watt microwave would use 1167 watts and 9.72 amps.
An 800-watt microwave would use 1333 watts and 11.11 amps.
A 900-watt microwave would use 1500 watts and 12.50 amps.
A 1000-watt microwave would use 1667 watts and 13.89 amps.
A 1200-watt microwave would use 2000 watts and 16.67 amps.
A 1500-watt microwave would use 2500 watts and 20.83 amps.
A 2000-watt microwave would use 3333 watts and 27.78 amps.

And if you have a 230-volt power supply and 60% efficiency:

A 600-watt microwave would use 1000 watts and 4.35 amps.
A 700-watt microwave would use 1167 watts and 5.07 amps.
An 800-watt microwave would use 1333 watts and 5.80 amps.
A 900-watt microwave would use 1500 watts and 6.52 amps.
A 1000-watt microwave would use 1667 watts and 7.24 amps.
A 1200-watt microwave would use 2000 watts and 8.70 amps.
A 1500-watt microwave would use 2500 watts and 10.87 amps.
A 2000-watt microwave would use 3333 watts and 14.49 amps.

However, keep in mind that this is just a rough guide based on the average efficiency for all microwaves, old and new. Newer model microwaves are much more likely to have an efficiency of around 70% or better.

Power settings

The final thing to consider is the settings on your microwave. Just because a microwave’s stated wattage is 1200, that doesn’t mean it uses 1200 watts of cooking power every time you use it. This rating refers to its maximum cooking power when set to the highest settings.

If you use the microwave on low or defrost modes, it will use considerably fewer watts and therefore draw fewer amps than when running at full power.

Sharing