How Many Amps Does a Microwave Use | Power Draw

Many people don’t give enough thought to how a microwave actually works. It’s easy to think of this appliance as just a box that heats up your food quickly. But if you take some time to learn how it actually works and how many amps it uses, you’ll be able to use your microwave in an optimal way and ensure that it remains in proper shape for a long time.

How Many Amps Does a Microwave Use

The amount of amperage your microwave will use depends on the model type and its manufacturer’s output power rating. If you have a standard 120-volt electrical outlet, you can easily calculate the amps your microwave draws, by dividing the output wattage by the voltage. This will give you the amperage. 

Here’s a simple table showing the amps used in relation to some of the most commonly used wattage.

600 watts800 watts1,000 watts1,200 watts1,500 watts1,800 watts
5 amps6.7 amps8.3 amps10 amps12.5 amps15 amps

What Is an Amp

Okay, so what exactly is an amp, which can also be referred to as an ampere? Well in short an amp represents a unit of electrical current. It is one of the standard units used to measure electricity. To help you visualize an amp, think about the rate at which an electrical current flows through a circuit. Or picture it as the number of electrons that move through a wire. A little bit like the volume of water flowing through a hose pipe, which we refer to as the flow rate.

I know some people aren’t too fond of physics and definitions like the one above, so I’m going to get practical now and explain what amperage is in relation to microwaves and any other type of electrical household appliance. 

In essence, the number of amps your microwave can draw, directly affects just how powerful the appliance is. In other words, the higher the number of amps the more heating or cooking your microwave will be able to perform over a period of time.

Why Microwave Wattage Matters

You may have noticed that microwave ovens with higher wattage usually come with a bigger price tag. There’s a good reason for this since wattage plays an important role in the time it takes for your food to heat up. Let’s say that you decide to replace your 800-watt microwave with a 1,500-watt model. That’s almost twice the wattage, which means that the cooking time will be significantly reduced when using the new microwave. You’re bound to notice a big difference when you compare the two models.

Calculating Microwave Power Draw

There is a notable difference between the input and output wattage of a microwave oven. This is because microwaves are estimated to be only 71.29% efficient at converting input power into output power. In other words, they convert electricity into cooking power at an efficiency rate of 71.29%. With the remaining 28.71% being lost throughout the power conversion process.

This means when calculating a microwave’s power draw, you need to multiply the output wattage by 100 and then divide the number you get by 71.29 to get a good estimate of the input wattage.

For example, with a 600-watt microwave, you would calculate input wattages using this simple formula: (600 watts X 100) = 6000 watts / 71.29 = 841.6 watts

Below is a table of the input wattage for some of the most common types of microwaves on the market today.

Output Wattage600 watts800 watts1,000 watts1,200 watts1,500 watts1,800 watts
Input Wattage841.6 watts1122.2 watts1402.7 watts1683.3 watts2104.1 watts2524.9 watts

Low vs High Wattage Microwave Ovens

There are several things you’ll have to consider before buying a microwave, including its biometric size, power rating, price, and of course the reliability of the brand or make. You’ll have to make a decision between purchasing a low-wattage or a high-wattage microwave, with the difference being both the physical size of the machines and the performance, in terms of the time it takes to heat food.

Advantages of Low-Watt Microwaves

  • Typically smaller, more compact units
  • Cost less to run than higher-watt models, but may take longer to heat some foods
  • Lower initial purchase price and lower replacement cost

Advantages of High-Watt Microwaves

  • Generally have a higher level of program options and functionality
  • Deliver more power over a shorter period of time, leading to heating food faster
  • Typically heat food more evenly

Microwave Wattage and Cooking Times

It’s often the case that people either undercook or overcook food in their microwave. This is usually down to users forgetting that microwaves come with different power outputs and therefore heat food at slightly different speeds. Make sure you get to know your microwave by reading the manufacturer’s instructions and following the guidance provided by food manufacturer’s on their packaging, as this will usually be based on a specific microwave power output. If you want to test the power level of your microwave, you can do a simple test that involves boiling water.

Boil a cupful of cold water in a microwave-safe pyrex jug, if it takes 4 minutes to boil, then you have a 600-watt microwave. If it takes 2 and a half minutes to boil, you will have an 800-watt microwave. The boiling time is lowered to 2 minutes for 1,000-watt microwaves and 1 and a half minutes for 1,200-watt microwaves. This test clearly demonstrates to reduced heating time of using a high-power output microwave.

If you find a recipe that is made for a microwave with a lower wattage than yours, all you have to do is appropriately set the power. Let me give you an example. Say you find a recipe that involves cooking food for 2 minutes in a 600-watt microwave, but you have a microwave with a power rating of 1,000 watts. All you have to do is program the power to 60% using the control panel, and it will mimic a model with a lower wattage.

Now let’s say that you have a 1,000-watt microwave and you’re following a recipe made for a 1,200-watt model. All you’ll need to do is add an additional 10 seconds for every 100 watts for each minute of cooking time.

The Cost of Running a Microwave

It’s pretty simple to calculate the running costs of a microwave oven. I’ll show you how to do it in the following example. Let’s say that you have a 1,200-watt microwave. If you remember our earlier formula,… we know microwaves are 71.29% efficient, so a 1200-watt microwave consumes 1,683 watts per hour.

Another way to represent this amount of power consumption is to say that the appliance consumes 1,683 watt-hours of electricity. You can also say that it consumes 1.683 kWh (kilowatt-hour) of electricity.

The average person doesn’t use a microwave for a very long time on a daily basis. For the sake of this example let’s say that you use your microwave for 1 hour every day of the month. 

If you would multiply 1.683 (the number of kilowatt-hours your microwave consumes) by 30 (the number of hours your microwave would be working in a 30-day month) you’d get 50.49 kWh of electricity. 

That’s the amount of power your microwave would consume on a monthly basis on average under the aforementioned conditions.

The cost of a kilowatt-hour of electricity varies heavily depending on where you live in. For this example, we’ll say that you pay for electricity at a rate of $0.2 per kWh. Multiply that number by 50.49 and you’ll see that running a 1,200-watt microwave for 1 hour each day would cost you $10.10 on a monthly basis. So on balance microwaves are actually pretty cost-efficient for cooking and reheating food.

Saving Energy When Using Your Microwave Oven

Microwaves are relatively energy efficient compared to ovens. They’re already a great way to save money as opposed to heating food in a gas or electric oven. However, the only downside is that there is a limit to how much food you can put in a microwave. It’s great for heating food for one person at a time. But if you’re preparing a meal for a whole family, you’ll most likely have to use an oven.

Although they’re energy-efficient, there are certain ways to even further reduce the cost of running your microwave. Here are some of the top ways to lower the cost of running a microwave.

Unplug the Microwave When It’s Not in Use

The microwave will use electricity when on standby. So why not try and reduce the cost of running a microwave by unplugging it when it’s not in use?

Cook Food for the Appropriate Time

Overheating food is a common problem. Just think how often you remove food from your microwave and it is ridiculously hot or even beginning to dehydrate around the edges. I know I’m guilty of throwing food in my microwave and just hitting 3 minutes and walking away until it beeps. Check the food cooking instructions, account for your microwave power, and be more accurate with cooking times.

Use the Eco Mode

Many microwaves, including most of the newer models, have an eco mode. Turning it on when you’re using the microwave is a great way to reduce energy costs.

Find a More Efficient Microwave

You may already have a microwave that you’ve been using for years. Although it may work fine, it’s likely that it uses more energy than most newer models. Technology is evolving quickly, and microwaves that are being released now are incredibly more efficient than the ones that were released 5 or 10 years ago.

Verdict: How Many Amps Does a Microwave Use

The number of amps your microwave uses ultimately depends on the output wattage and the voltage. In the United States, 120-volt electrical outlets are the standard. The output wattage varies depending on the model of your microwave oven. You can easily calculate how many amps your microwave uses by dividing the output wattage by the voltage.

FAQs Do Microwaves Pull a Lot of Amps?

Appliance Service Technician | Website | + posts

Andy has over 8 years of experience working on residential household appliances, performing diagnostics, and repairs across most major brands. He graduated from the Denver Institute of Technology, is NASTeC certified, and has worked for Mr. Appliance. Andy has contributed to features on major publications including Better Home & Gardens, Family Handyman, and