Last updated: February 5, 2024.
How many watts does a microwave use? (It’s not as obvious as you might think) Find out here. See which is the most energy efficient microwave in 2024, based on 203 models, and use this microwave wattage conversion calculator to adjust recommended cooking times.
Based on 203 models, below you’ll get key microwave wattage and power consumption results, along with useful conversion calculators and insights into energy efficiency (incl. the stand out model).
- Microwave wattage ranges from 600W to 2100W, but 1000W is the most common. However, microwave power consumption is higher than the listed wattage.
- On average, microwaves consume between .8416 kWh and 2.9458 kWh of electricity per hour, with 1.4027 kWh being the most common.
- Microwaves are 71.29% efficient, on average, at converting input power into cooking power based on the data captured in this study.
- Converting an impressive 92.59% of electricity into cooking power, the 1250W Toshiba ML-EM45PIT(BS) inverter microwave stands out in terms of energy efficiency.
Continue reading to get more microwave wattage details including the difference between input and output wattage, how to find the wattage of your microwave, and which type of microwave is most efficient.
You’ll also get a useful Microwave Wattage Conversion Time Calculator to help you convert recommended cooking times for any microwave wattage to suit your microwave’s wattage.
The stats used in this post are based on the microwave wattage of 203 different countertop microwaves. An average input wattage was used to identify the energy efficiency levels. Microwave energy efficiency levels in this post refers to the conversion rate of input power (the max power rating of the microwave, in watts) to output power (the maximum cooking power stated by the appliance, in watts) – see “Efficiency sidenote” below. The “most common wattage” refers to the microwave wattage that is most commonly stocked by retailers, not the most commonly used by consumers.
- Microwave wattage
- Microwave input vs output wattage
- Microwave energy efficiency
- How many watts does a microwave use
- How much electricity does a microwave use (in kWh)
- Microwave wattage conversion
- Don't miss…
Microwave wattage ranges from 600W to 2100W, with 1000W being the most common.
However, the amount of watts that a microwave actually uses is higher than its stated wattage.
Microwaves use between 841.6W and 2945.8W, with 1402.7W being the most common amount of watts used.
This is based on research into the wattage of 203 countertop microwaves.
Microwave wattage and the amount of watts they actually use are different because the output wattage is different from the input wattage.
Let’s briefly take a look at this in more detail.
Microwave input vs output wattage
Microwave input wattage is the amount of watts that the appliance uses. In other words, it’s the actual power consumption of the appliance.
Microwave output wattage refers to the amount of microwave energy made available for heating. Microwave output wattage is also known as the cooking wattage.
Microwave output wattage is the figure that’s most commonly used. This is the wattage listed in cooking instructions, highlighted most by manufacturers, and referred to in most discussions.
As mentioned, 1000W is the most common microwave wattage (i.e. output wattage). However, the input wattage (i.e. the actual power consumption) of a 1000W microwave is 1402.7W on average.
Microwave input wattage is always higher than the output wattage. This is because microwaves are not 100% efficient at converting electrical energy into microwave energy.
In saying this, however, microwaves are one of the most energy efficient cooking appliances. Let’s take a look at microwave energy efficiency in more detail.
Microwave energy efficiency
Microwaves are 71.29% efficient at converting input power into output power, on average.
In other words, on average, microwaves convert 71.29% of electricity into microwave cooking power based on results from this study.
Efficiency sidenote: Numerous factors influence microwave efficiency. I coudn’t find an authoritative source with a modern, comprehensive, and robust estimate of this efficiency. Consequently, I derived an efficiency estimate for popular contemporary microwaves (a mix of types) by comparing the input and output power ratings as provided by the manufacturers. This method offers a rough estimate of the efficiency of modern microwaves.
While there are more scientific approaches, the results remain highly dependent on various factors. My hypothesis is: Using the most popular models, and this method to estimate efficiency, will yield an efficiency estimate that more accurately reflects the current landscape. Additionally, it is hoped that this will serve as a valuable starting point for further analysis and discussion.
For example, a 600W microwave actually consumes 841.6W on average.
Some countertop microwaves are more efficient than others.
Modern countertop microwave efficiency can be as low as 54%, in some cases, to 93% and higher in others.
Inverter microwaves are more efficient than conventional microwaves. A key difference is that, instead of using a transformer, inverter microwaves offer more control over the magnetron. This enables greater power control, and therefore, offers more efficient heating.
Microwaves in general are the most efficient cooking appliance. Although, there are occasions where conventional cooking appliances are actually more efficient – more on this in a moment.
Microwaves are more efficient because they cook from the inside out.
Sidenote: microwaves don’t cook from the center out. The waves reach a depth of approx. 1-2 inches, depending on the power of the microwave. The heat created then transfers throughout the food. Regular microwaves actually heat specific areas (around 3-4 inches apart) of the food, and the areas heated depends on where the food is placed in the microwave. Inverter microwaves, on the other hand, deliver more consistent heating.
As a result, there is less heat and energy wastage from microwaves compared to conventional cooking appliances.
Convection ovens and conventional cookers heat the area surrounding the food, to then cook from the outside in. This is a slower and more inefficient mode of cooking.
In saying this, however, conventional cookers can be a more efficient appliance if you’re cooking a lot of food at one time.
But if you’re cooking or reheating a single bowl of food, for example, a microwave is a more efficient appliance.
Also, it’s worth noting that microwave output wattage is not a key energy efficiency factor.
A 700W microwave is not more efficient than a 1200W microwave. It just means that you’ll have to cook the food for longer.
In the end, you’ll consume a similar amount of power when cooking.
This of course assumes that both microwaves are similar (e.g. they’re both regular microwaves).
Microwaves are becoming increasingly diverse.
Many modern microwaves come equipped with a grill / heating element, which offers more cooking versatility while still delivering energy efficient heating.
Ultimately, when it comes to energy efficiency, the appliance that has the least amount of energy wastage that also meets your needs tends to be the most energy efficient option.
If a microwave is suitable for you, here’s a stand out energy efficient model…
Energy efficient microwave
The 1250W Toshiba ML-EM45PIT(BS) inverter microwave stands out in terms of energy efficiency.
It also has a compelling price and design, along with exceptional reviews and high-tech features.
Check it out, here.
This energy efficient microwave converts an impressive 92.59% (71.29% is average) of its input wattage into output power.
With a maximum input wattage of 1350W, this inverter microwave can output 1250W.
This amount of efficient power means that you’ll spend less time heating. The manufacturer even notes that this appliance saves up to 40% on defrosting time.
The smart cooking sensors, the amount of power control, and the energy saving Eco Mode feature are other key factors that made this microwave stand out.
Get more details on this energy efficient microwave, including the price, here.
You may be interested in: Dishwasher Wattage [601 Studied | Most Efficient Revealed].
OK, now that we’ve looked at microwave energy efficiency and know the difference between input and output power, let’s take a look at how many watts different sized microwaves use.
How many watts does a microwave use
Microwaves use between 841.6 watts and 2945.8 watts to deliver between 600 watts and 2100 watts of cooking power.
The most common microwave cooking power is 1000W, which uses 1402.7 watts on average.
This is based on research into the wattage of 203 countertop microwaves in 2024, and uses the average input to output wattage efficiency of 71.29%.
Retailers tend to categorize countertop microwaves into small and medium size categories. Unfortunately, the size range isn’t standardized across retailers.
Interestingly, the amount of watts that a microwave uses doesn’t vary dramatically across both small and medium size categories.
Small microwaves output between 600 and 2100 watts of cooking power, using between 841.6 watts and 2945.8 watts of electricity.
The most common small microwave output wattage is 700W, which uses 981.9 watts on average.
Medium size microwave wattage doesn’t vary quite as dramatically.
Medium size microwaves deliver 800W to 2100W of cooking power, consuming between 1122.2 watts and 2945.8 watts of electricity.
The most common medium sized microwave output wattage is 1000W, which, as mentioned, uses 1402.7 watts on average.
The table below lists the average amount of watts used by a microwave based on its power output (i.e. cooking power).
|Microwave wattage (i.e. output wattage / cooking power)
|Microwave power consumption (i.e. input wattage)
Again, the input wattage is based on the average microwave efficiency (i.e. 71.29%) at converting input wattage into output power (which is also listed as watts).
In case your microwave wattage is not listed above, here’s a useful Microwave Power Consumption Calculator.
Microwave power consumption calculator
Microwave wattage generally refers to the cooking power of a microwave, not its power consumption.
To estimate the power consumption of your microwave, enter the cooking power (i.e. output wattage) into the calculator below. Also, enter your estimated daily usage to see how many watts your microwave uses per hour, day, week and month.
By default, the calculator is pre-populated with the estimated power consumption for a 1000W microwave that’s used for 10 minutes per day at max power.
This calculator estimates the power consumption of a microwave based on the cooking power using the average microwave efficiency (71.29%) at converting input to output wattage.
As mentioned, some microwaves, particularly inverter microwaves, are more efficient than others at converting input electricity into cooking power.
Next, let’s take a look at how you can find the manufacturer’s listed wattage (both the input and output wattage) of your microwave.
How to find the wattage of a microwave
There are several ways to find the wattage of your microwave.
To find your microwave’s output wattage:
- Check the plate at the back of your microwave for the listed wattage.
- Check the inside of the microwave door (or the outside in some cases).
- Check the owner’s manual.
- Look online using your microwave’s model number.
- Estimate the wattage using the “time-to-boil test”.
The “time-to-boil test” estimates microwave wattage from how long it takes your microwave to boil 1 cup of ice cold water.
Your microwave is 1000W or more if it boils 1 cup of ice cold water in less than 2 minutes. It’s 800W to less than 1000W if it boils the water in around 2.5 minutes, it’s 650W to 700W or higher if it boils in 3 minutes, and finally if it takes more than 3 minutes then your microwave is likely 300W to 500W.
Finding your microwave’s input wattage is different, but there is some overlap.
To find your microwave’s input wattage (i.e. power consumption):
- Check the plate at the back of your microwave for input power (i.e. the maximum wattage that the device can use). This will be higher than the output power, which is also listed in watts.
- Check the owner’s manual. Look for the input wattage figure not the output power figure.
- Look online using your microwave’s model number. Many online resources don’t make the input wattage easily accessible. You may need to find the owner’s manual online and then search within it to find the power consumption.
- Estimate the input wattage from the output wattage. On average, microwaves convert 71.29% of their input power into cooking power. So if you know your microwave’s output wattage, you can work out the input wattage yourself or simply use the Microwave Power Consumption Calculator above. However, your microwave may be more or less efficient than average. The next point is the best way to accurately identify your microwave’s actual power consumption.
- Use a multimeter or energy monitor to see how many watts the microwave is using when it’s running. A smart plug, with an energy monitor feature, may be useful, e.g. the one I use is the KASA smart plug (check it out, here).
It’s important to know the input wattage of a microwave because it gives you a sense of the impact your microwave is having on your electric bills and carbon footprint.
Now that we know how you can find your microwave’s input wattage, and since we’ve covered how many watts microwaves use on average, next let’s take a look at how much electricity (in kWh) they use. And let’s also put things into perspective by comparing microwave power consumption with the power consumption of other household appliances.
How much electricity does a microwave use (in kWh)
On average, microwaves consume between .8416 kWh and 2.9458 kWh of electricity per hour, with 1.4027 kWh being the most common.
Based on research into 203 microwaves, 1000W microwaves are the most stocked by retailers in the US.
On average, 1000W microwaves consume 0.0234 kWh of electricity (max) every 1 minute.
But is this a lot?
Related: Toaster Wattage Results [Lowest Wattage & Cost Per Use Revealed].
Do microwaves use a lot of electricity
Yes. Microwaves use a lot of electricity.
The listed microwave wattage tends to be less than ¾ of the amount of electricity that the appliance actually consumes.
For example, and as mentioned, a 1000W microwave uses 1402.7W or 1.4027 kWh of electricity per hour, on average.
High powered microwaves use even more electricity, at nearly 3 kWh per hour.
High power microwaves can use more than 3 times the amount of electricity compared to low power microwaves.
So microwaves, particularly the high powered models, use a lot of electricity.
Let’s get some perspective by comparing how much electricity a microwave uses with the electricity consumption of other standard household appliances, and even a Tesla.
Running a 1000W microwave for 10 minutes is equivalent to:
- How many watts a TV uses after running for close to 4 hours.
- How much electricity a ceiling fan uses (specifically a medium sized ceiling fan) after running for nearly 13 hours.
- How much electricity a Tesla Model 3 uses per mile of driving.
It’s increasingly common to find microwaves in homes that have a considerably higher wattage than 1000W.
However, despite using a lot of electricity, microwaves are very efficient when it comes to cooking.
As mentioned, it’s important to understand the microwave power consumption / input wattage. But it’s particularly important to know the output wattage (i.e. cooking power) of your microwave.
This is because cooking instructions give cooking times for specific wattages. Thinking you have a more powerful microwave than you actually have can lead to undercooked food. This is obviously unsafe and can lead to illness.
An added problem is that you may need to alter cooking times if your microwave wattage is not the same as what is listed in the cooking instructions.
To help ensure you cook your food appropriately use the Microwave Wattage Conversion Time Calculator below.
Microwave wattage conversion
When your microwave output wattage does not match the wattage listed in the cooking instructions, you need to cook your food for a longer period of time.
This is an increasingly common problem due to microwave wattage becoming more and more diverse.
To help ensure that you cook your food safely, here’s how to convert cooking times for microwaves that have different output wattages.
If you don’t want to do the math, skip to the Microwave Wattage Conversion Time Calculator section below.
3 steps to convert microwave cooking times
- Divide the microwave wattage listed in the cooking instructions by your microwave wattage.
- Convert the listed cooking time into seconds, if necessary.
- Multiply step 1 by step 2.
The result gives you the recommended cooking duration, in seconds, for your microwave.
Here’s the formula:
Your Cooking Time = (Microwave Wattage Listed / Your Microwave Wattage) * Recommended Cooking Time In Seconds
Let’s look at an example, following the 3 steps and using the formula.
Say you have a 1000 watt microwave and the instructions recommend cooking for 3 minutes in an 800W microwave. Here’s how you can convert the cooking time.
- Divide 800 (the wattage listed in the cooking instructions) by 1000 (your microwave wattage). This gives you 0.8.
- Convert 3 minutes (the recommended cooking time listed in the instructions) into seconds. The result is 180.
- Multiply 0.8 by 180, and you get 144.
This means that the recommended cooking time for your microwave is 144 seconds or 2 minutes 24 seconds.
Here’s how it looks in the formula:
Your Cooking Time = (800/1000)*180
Not interested in doing the math? Use the following Microwave Wattage Conversion Time Calculator.
Microwave wattage conversion time calculator
Use the calculator below when your microwave wattage does not match the microwave wattage listed in the cooking instructions.
This calculator converts recommended cooking times into a cooking time suited to your microwave.
Simply enter the microwave wattage listed in the cooking instructions, your microwave wattage (i.e. the output wattage / cooking power) and the recommended cooking time.
By default, the calculator is pre-populated, converting a 5 minute (300 second) recommended cooking time for a 900W microwave into the corresponding cooking time for a 1250W microwave.
The standard disclaimer: always ensure that your food is cooked thoroughly throughout before consuming it. The calculator / calculations above, your cooking instructions and even your microwave’s output power may not be accurate, so please ensure that your food is safe to eat.
Now that we’ve looked at wattage, conversion times, and how many kWh of electricity microwaves use, let’s take at some frequently asked questions that I came across while researching the energy efficiency of 203 microwaves.
The below are common questions that I came across during my research into microwave energy efficiency.
Microwave wattage is becoming increasingly diverse and can be a confusing topic.
I hope that the Microwave Wattage Conversion Time Calculator helps you to conveniently ensure that you’re cooking your meals appropriately in this increasingly diverse appliance category.
And I hope that this post clarified the difference between input and output wattage, and gave you insight into the actual power consumption and efficiency of microwaves.
If you’re in the market for a new microwave, check out the 1250W Toshiba ML-EM45PIT(BS) inverter microwave, here.
This model stands out in many ways, but particularly for its energy efficiency. It’ll help keep your electric bills and carbon footprint low.
Interesting in knowing what impact your microwave is having on your electricity bills, and how to limit the impact? Don’t miss: Cost To Run A Microwave [5 Cost Saving Tips].
And you won’t want to miss this cost-free Quick Wins Cheat Sheet either – it’ll help you reduce your overall electricity bills and carbon footprint considerably:
How much does it cost to run a dishwasher? Find out here, based on 601 models. Plus, see how you can reduce the cost to run a dishwasher with these 6 useful tips.
How much water does a dishwasher use? Find out here, based on 601 models. See dishwasher water usage by cycle, month and year, and see which dishwasher uses the least amount of water, and more.
How much electricity does a dishwasher use? Find out here, based on 601 models. Plus, see which is the most energy efficient dishwasher and find the electricity usage per cycle by brand.
James F (not to be confused with ECS co-founder James) is our lead author, content & website manager. He has a BSc. in Digital Marketing, and a Diploma in IT. He became a qualified electrician while studying electrical engineering part-time.
From wind and solar photovoltaic installers, James F worked with many certified energy practitioners and energy consultants before joining the core ECS team. He also helped build the most downloaded energy saving app while working with a leading utility company.