Microwaves differ in terms of the number of amps they use and their specific electrical requirements. Standard microwaves consume 8.3 amps on average, but other factors, like wattage, largely determine this. Let’s look at how many amps your microwave needs, regardless of wattage, microwave size, or circuit.

How does a microwave work?

The microwaves’ direct action generates intermolecular friction between the water molecules and the food molecules in a microwave oven. The vibration of the molecules generates heat, which cooks the food.

To start cooking or reheating, you must click specific buttons, and you may swiftly produce a meal in a matter of minutes.

You might be wondering how a microwave converts electricity (microwave amp) into heat. When the magnetron inside the oven produces high-powered microwaves from electricity, this action is conceivable. The magnetron then directs these microwaves into the slowly rotating food turntable.

Microwaves bounce back and forth from the wall of the food chamber, penetrating the food. The food’s molecules will vibrate faster as a result of this happening. The frictional heat created by the vibration of these molecules against each other heats or cooks the food.

What is amperage?

Amperage (amps) is a unit of measurement for the number of electrons in an electrical circuit.

Higher amperage normally equates to a higher power. However, amperage and voltage operate in tandem to achieve the final output.

Voltage is a type of electrical current that measures pressure rather than the number of electrons.

Multiply the amperage and voltage of a device to get the watts, which is an all-encompassing measurement of power.

But how many amps does it use?

Surprisingly, both manufacturers and electricians will inform you that a 15- to 20-amp circuit is required. The reason for this is that, just because your microwave oven produces 1,000 watts does not mean it only consumes that amount. In reality, a 1,000-watt microwave oven will normally use approximately 1,700 watts.

How do you calculate amps draw?

The figures above are provided for information only; you may compute the current (amps) drawn by a microwave, yourself, using the following formula:

You will need to know the input power and standard wall voltage in your country to utilize this formula. Again, the standard voltage in the United States is 120 volts, but in Europe and Asia, it is 220 volts.

The beauty of this equation is that it applies to all electrical equipment. In essence, all you need to know is the appliance’s input power. Voltage is, for the most part, well understood.

However, when calculating the current drawn, you must use the INPUT POWER value rather than the OUTPUT POWER value.

Input and output power

Microwave ovens, like all other equipment, have two power ratings: input power and output power.

You’ll also observe that a microwave oven’s output power is substantially lower than its input power.

This is because no electrical equipment is completely efficient. Microwave ovens are approximately 65% efficient. This means that 65% of the power drawn (Input Power) is turned into microwave energy (Output Power).

A 700W microwave oven, for example, regarded as the weakest microwave class for residential use, uses approximately 1100 Watts of electricity if it has a standard efficiency of 65 per cent.

Let’s look at some typical input and output power values. The output power value, in this case, is based on a 65 percent efficiency.

  • 1100 W Input – 700 W Output
  • 1350 W Input – 900 W Output
  • 1700 W Input – 1100 W Output

It should be remembered that efficiency varies from model to model. Some are more efficient than others at converting the input power to output microwave energy.

The most powerful class of microwave ovens for residential usage typically have an output power of 1250 W, while these would draw approximately 1850 W.

The important thing to remember here is that you must use the significantly larger Input Power value when calculating the amps. The higher the power, the higher the amp drawn.

Microwave oven wattage

There are various ways to determine how many watts your microwave oven uses, if you don’t know. First and foremost, it should be included in your owner’s manual. However, many of us either tossed it away or misplaced it within a week of receiving the microwave oven, correct?

If you can’t find your owner’s manual, you may always check your microwave oven. In most situations, the input and output wattage should be listed on the inside of the door. If not, look at one of your microwave oven’s internal walls. You’ll also notice the voltage, which is normally 120 volts.

Try boiling some water

There is a less precise method for determining the wattage of your microwave oven. It’s not as professional, but it’s fascinating. It’s called the boil test. The time it takes your microwave oven to boil one cup of water will provide you with the necessary answer.

This is not an exact science

This approach, however, has certain disadvantages. To begin with, depending on the container you choose, the water may boil at a different time. These times will work great if you use a standard ceramic coffee mug. When water boils in a glass, though, it is easier to see. Use a thick glass, such as a glass measuring cup, and the results should be identical to those of your coffee cup.

The watts and amps

It’s a little different story if you’re concerned about how many amps your microwave oven consumes due to your circuits. On whatever circuit you use, you can only load up to 80% of the rating. For example, if you have a 1,000-watt microwave oven that draws 1,700 watts, you cannot use a 15-amp circuit.

To calculate the watts available for a circuit, multiply the amps by the volts. The maximum wattage that a 15-amp circuit with 120 volts can provide is 1,800. And 80% of 1,800 equals 1,440. This is insufficient to power a 1,000-watt microwave oven. Assuming you use a 20-amp circuit, the maximum wattage is 1,920, which is plenty for a 1,000-watt microwave oven.

High watt vs Low watt microwaves

When shopping for microwaves, how do you decide whether to choose the 1200-watt or 600-watt models?

Learn the key distinctions between high-wattage and low-wattage microwaves to make the best purchasing decision.

Pros and cons of high wattage microwaves (800 watts or more)

Pros:

High-watt microwaves cook food faster, making them the favored alternative for impatient, hungry people.

The quick cooking time also reduces the danger of becoming ill from consuming partially cooked food.

The food also cooks more evenly, so you don’t have to flip it as much to get it properly heated.

Cons:

Higher wattage microwaves are more expensive and require more power from your electrical outlets.

Pros and cons of low wattage microwaves (less than 800 watts)

Pros: Low-wattage microwaves use less energy, which saves you money on your electricity costs.

They are also less expensive upfront and will not put undue strain on lower amperage wiring found in an RV or boat.

Cons: You will have to wait much longer for your food, which reduces the savings from running more efficiently.

People may also be served raw food, which can cause diseases.

How fast are high watt microwaves compared to low watt microwaves?

How much of a difference does wattage make?

See how long it takes a microwave to boil water at various wattages for a visual representation:

  • 600 watts = 2:55
  • 800 watts = 2:11
  • 1000 watts = 1:45
  • 1200 watts = 1:27

The effect microwave amperage has on you

What will you do with your new microwave amperage knowledge?

You can use it to make informed purchasing decisions and ensure correct microwave electrical wiring.

The importance of understanding microwave amp draw

When measuring electrical components or creating a circuit design for your kitchen, the amps drawn by any device are important considerations.

1. Circuit design

Before you design your kitchen circuit, you must determine the number of amps (load) linked to it.

A typical kitchen layout may include two dedicated 20 amp circuits. However, if you have a large number of high-powered appliances, such as a strong microwave oven, you may want extra dedicated circuits.

Dedicated branch circuit

A separate breaker protects a dedicated circuit. The breakers have their own Amp rating, such as 15 Amps, 20 Amps, etc. This indicates that if the total connected amperage of the appliances exceeds the breaker amperage rating, the breaker will trip.

This is for your protection against power surges and short circuits.

According to National Electrical Code, a single breaker should not be utilized at more than 80% of its amperage rating. As a result, the maximum connected load to a 20 Amp breaker should not exceed 16 Amps. Similarly, a 15 Amp breaker should not be connected to a device (or devices) requiring more than 12 Amps of current.

As a result, if you have a high powered countertop microwave oven with a rated input power of 1850W, drawing roughly 15 Amps of current at 120 Volts (as previously noted), you will need to establish a dedicated branch circuit with at least a 20 Amp breaker.

It should also be noted that the current drawn by fastened or installed microwave ovens such as over-the-range microwaves or built-in microwaves should not exceed 50% of the breaker rating (according to American Standards)

Fuse and component size

Everything from diodes to capacitors to fuses is affected by the amount of current drawn.

For example, like a breaker, a fuse blocks the electrical current if there is a short circuit or a power surge.

A fuse is typically sized at roughly 135 percent of a device’s rated input current. So, if your microwave oven draws approximately 10 Amps of electricity, the fuse should be rated at approximately 13.5 Amps for your protection.

2. Extension cord gauge

While using a high-powered electrical device over an extension cord is not suggested, if you absolutely must, you must examine your device’s input current and then choose the corresponding gauge (diameter) of the extension cable.

The higher the current drawn, the thicker the cable required.

The American Wire Gauge Standard is used in the United States.

The lower the AWG number, the larger the diameter of the cable and thus the greater the current capacity.

If you want to use a microwave oven over an extension cable that draws 15 amps of current, you will need at least a 14 Gauge AWG cable.

Of course, the thicker the cable, the higher the price.

Related questions

How do I know if my microwave is malfunctioning?

A circuit breaker may trip as a result of a defective microwave (or other equipment). If the microwave is overloading the circuit despite not drawing more watts than is recommended, the microwave may be defective. To put the microwave to the test, do the following: 

  • Step 1: Plug it. Plug up your microwave oven in a higher-amperage region, such as your garage or workroom.
  • Step 2: Turn it on. Check out what occurs when you turn on your microwave oven.
  • Step 3: If it slips or if the circuit breaker also trips, the problem is with the microwave, not the circuit breaker. You should either dispose of it or repair it.
  • Step 4: If it does not trip and the circuit breaker does not trip, there is no problem with the microwave. You must connect your microwave to a higher-amperage circuit.

How many watts does a microwave need?

In most circumstances, 1,000 watts is sufficient wattage for a residential microwave. For microwave ovens, this would be considered moderate power. Of course, the higher the wattage of your microwave, the more power it has. More power means your food will be cooked more evenly and quickly.

Is it possible to increase the amperage in my breaker box?

You should consult a professional electrician before increasing the amps of any of your circuit breakers in the breaker box. When your home is wired, the breakers are carefully calculated to ensure that the electrical system does not overload the wiring.

You could cause an electrical overload or even a fire if you boost the amps of one of your breakers without knowing what you’re doing. However, if you speak with an electrician and have their approval, the job is not too difficult.

Step 1: Turn Off the Power. When working on anything electrical in your home, always switch off the power. Turn on a light or use an outlet to ensure it is turned off.

Step 2: Take out the Panel. Remove the outer panel by unscrewing the screws and pulling the cover off.

Step 3: Disconnect the circuit breaker. Take the circuit breaker that has to be replaced out of the box. It should come out immediately.

Step 4: Install the New Breaker. Check that it is not higher than what the electrician has approved. Replace the panel and switch on the power. That’s the only thing there is to it.

Is a 20-amp circuit required for a microwave?

The microwave oven requires a dedicated 20-amp, 120/125-volt circuit. This requires the usage of a 12/2 NM wire with a ground. While regular appliance outlets are routinely used for microwave ovens, larger microwave ovens can consume up to 1500 watts, so they require their dedicated circuits.

What is the amp draw of an 1100 watt microwave?

Approximately 10 amps.

Divide the wattage by the line voltage (usually 110v in the United States) to get amps, as P (power) = V (volts) x I (current). As a result, an 1100 watt oven operating at 110 volts consumes 10 amps.

Is a dedicated circuit required for a 1000 watt microwave?

No, it is not. A 15 amp receptacle can handle up to 1800 watts, whereas a 20 amp receptacle can handle 2400 watts. In the United States, two 20-amp kitchen circuits normally provide all kitchen general-use and dining room outlets, including the refrigerator.