What Size Inverter to Run a Microwave?

By:Michael Johns

inverter for microwave

Choosing the right size inverter to run your microwave is critical.

Microwaves are power-hungry appliances and it can be tricky to work out what inverter size you need.

If you get it wrong, you’ll be left frustrated with a useless inverter, unworkable microwave, and a cold bowl of beans… 

And trust me when I say, cold baked beans is the worst of those three.

Plus, in your off-grid setup, the microwave might be the only cooking appliance you have for breakfast, lunch, and dinner.

But don’t worry. Take a breath and keep reading because I’ll help you find the right power inverter for your microwave.

Together we’ll go through the inverter size, factors to consider, best products, and questions like – will a 1000 watt inverter run a microwave?

What Size Inverter Do I Need to Run a Microwave?

A 1500 watt inverter should be big enough to run a microwave.

The average home microwave uses between 600 and 1200 watts. 

Of course, each brand and model of microwave requires a different amount of power.

But a 1500 watt inverter will be able to handle most domestic microwaves as long as it has a peak surge capacity of at least 3000 watts. This is because a microwave uses extra power when first switched on for a few seconds. Any decent inverter should have a peak power rating of double its continuous wattage capacity.

It’s easy to identify the size of an inverter as the products are named after their size such as 500 watt inverter, 1000 watt inverter, 1500 watt inverter, and so on.

How Many Watts Is My Microwave?

As I mentioned above, it’s likely your microwave uses between 600 – 1200 watts. This is determined by the size of your microwave.

For example, a small microwave designed for students might use around 600 watts while a large family microwave can use 1200 watts.

As you can imagine, the more powerful the microwave, the faster and more evenly it cooks your food.

So how do you find your microwave watts? Well, there’s a couple of very easy ways.

Firstly, you can check the technical specification/user manual. There is often a sticker on the appliances to tell you the power requirements. If you don’t have this information you can always contact the manufacturer to find out.

Secondly, I like to use a wattmeter which you can attach to any appliance to get live readings of watts, amps, and volts. I highly recommend this as it gives you a definitive reading for your setup.

It shouldn’t be too hard to work out what size microwave and what size inverter you need. Both are sold in sizes of watts such as 700 watt microwave, 800 watt microwave, 900 watt microwave, and so on. 

Always use an inverter with 20% more watt capacity than your microwave as inverters are not 100% efficient. For example, with a 1000 watt microwave, you should use at least a 1200 watt inverter.

Peak Surge Power

You should also double-check the peak power your microwave needs for a second or two when you first switch it on. This surge can be double or triple the amount of the continuous power so you need to ensure your inverter can cope with this.

Pure Sine Wave is a Must

Before you go off and buy an inverter purely based on size, you should also know that you require a pure sine wave inverter. Pure sine wave is a type of AC output that is designed to replicate the mains electricity. It delivers a smooth flow of current which your microwave needs as it is an inductive appliance. 

You want to avoid the cheaper modified sine wave inverters as their steps in voltage won’t run your microwave properly. It will massively reduce efficiency, create an annoying buzzing noise, create excess heat, and even lead to long-term damage. Avoid!

Best Power Inverter for Microwaves

Now you understand what you need to run your microwave we can start to look at some of the best inverters available. Below I have shortlisted the top options for you to check out. All of these products have at least 1000 watts of pure sine wave output and are high-quality choices.

Consider Inverter Efficiency

I want to quickly address inverter efficiency to make sure you have enough capacity for your appliance. It is best practice to use an inverter with 20% more power than you want to draw.

This is because they are not 100% efficient, usually, they are between 85% and 95% efficient. Inverters lose energy in heat during the conversion of DC to AC, plus they need power to run internal systems such as cooling fans and digital screens.

To factor in inverter efficiency add 20%. You can do this with the following formula: microwave watts x 1.2 = minimum inverter size.

For example, 700 watts x 1.2 = 840 watt minimum inverter size.

Battery Size to Run a Microwave

So how long will an inverter run a microwave? Well, this depends on how much energy you use and the size of your batteries.

To run an inverter you need to hook up to a deep cycle battery or vehicle battery. Then you need to know how much energy your appliance uses and the battery size.

There are so many complicated equations, formulas, and advice on the inverter to solve this question! That’s why I’ve created this simple way to work out inverter runtime:

 (10 x battery capacity in amp hours) divided by (appliance load in watts) = runtime.

So let’s say we want to use a 700 watt microwave on a 100Ah battery. Using the formula above we calculate (10 x 100Ah) ÷ 700W = 1.4 hours.

You could run a microwave for 1.4 hours with 100Ah battery size. Remember, you won’t be constantly running your microwave for an hour. You’ll use it for seconds or minutes. To be honest, if you’re just nuking some noodles it’ll only be drawing power for a minute or two!

Protip: Traditional lead-acid batteries should not be discharged more than 50% as depleting them can cause damage. This means runtime is halved with lead-acid batteries.

Will a 1000 Watt Inverter Run a 700 Watt Microwave?

Yes, a 1000 watt inverter will run a 700 watt microwave as long as it is pure sine wave. To run a 700 watt microwave you need a very minimum of 840 watt inverter size but a 1000 watt inverter will cope better. 

You should not try to run an inverter on maximum or high load for long periods of time as their cooling systems may struggle to keep up.

Will a 1500 Watt Inverter Run a 700 Watt Microwave?

Yes, it is highly recommended to use at least a 1500 watt pure sine wave inverter to run a microwave. You will easily be able to power a 700 watt microwave with a 1500 watt power inverter.

Can You Run a Microwave Off a Car Battery?

It is possible to run a microwave from a car battery. Many people connect inverters to car batteries in order to create AC electricity from their vehicles. This enables you to run home appliances and tools!

Before trying this you should check the alternator output capacity to make sure it can keep up with the number of watts you want to draw. Alternators range in power from 500 – 2000 watts. If you draw more watts than your alternator can handle you will start to deplete your starter battery. You should also ensure your engine is switched on to recharge your battery. Never use an inverter without your engine running as you will deplete it very quickly leaving you stranded and damage to your car battery.

Can I Run My Microwave with Solar Panels?

It is possible to run a microwave with a solar panel system. Unfortunately, you can’t connect your microwave directly to your solar panels as it won’t offset consistent AC power to run. 

To use a microwave with solar panels you must connect your solar panels to a battery and inverter. This allows you to charge your battery with DC power from the solar panels. Then you can use your inverter to draw power in from the battery, convert it into AC output, and run your microwave.

Final Words on Inverter Size for Microwave

There you have it, everything you need to know about running a microwave with an inverter. Most of the factors to consider come down to size and power requirements.

I recommend using a 1500 watt inverter to run a domestic microwave. This should give you plenty of power without overloading your off-grid power supply.

Here’s a summary of the key considerations:

  • Inverter watt capacity should be at least 20% than microwave wattage
  • Ensure your inverter has enough peak power to deal with microwave surge when switching on
  • Use a pure sine wave power inverter
  • Microwaves use between 600 – 1200 watts
  • 1500 watt inverter should be good enough for most microwaves

If you want to explore more inverter options then read my guides to the Best Pure Sine Wave Inverter and Best 1500W Power Inverter.

Thanks for reading and happy nukin’.