Shopping for a new microwave oven? Do a little research on countertop and over-the-range microwave dimensions and capacities before you buy so you can find the right size for your space and cooking needs. A new microwave can help free up some counter space or streamline mealtime with the latest features, like convection. 

Not sure where to start? Keep reading to learn more about external and internal sizes for different microwaves types, then check out How to choose the right microwave.

What are standard microwave sizes?

There are two measurements to take into consideration when determining what size microwave to buy. The external dimensions, measured in inches, tell you the overall size of the microwave and help you determine how much space you’ll need to accommodate your appliance. The internal dimensions–or capacity–measured in cu. ft., indicate how much cooking space is available inside the microwave. Depending on space constraints in your kitchen, the depth of the appliance may be the most important factor in determining which size microwave is right for you.

Let’s take a look at the different microwave styles and configurations available:

Countertop microwaves

• Interior space ranges from 0.5 cubic feet (usually considered compact microwaves) to over 2.0 cubic feet.

• Exterior width ranges from roughly 15 inches for compact microwaves to 24 inches for larger units.

• Remember to consider the depth of the microwave with the door open to make sure you have enough space for the full swing-out.

  • Closed-door depths range from roughly 14" to 20"

  • Open-door depths range from roughly 27" to 39"

Over-the-range microwaves

• Interior space usually ranges from 0.8 cubic feet for compact microwaves up to 2.1 cubic feet for full-sized models. The industry-first Low Profile Microwave Hood Combination by Whirlpool brand brings together the best of both worlds with a space-saving design and 1.1 cubic feet of interior space, plenty of room to fit tall glasses, wide plates and big bowls.

• Widths will usually be roughly 30" to match the standard width of the range below and the standard cabinet width where the microwave will be mounted.

• Most over-the-range microwaves are roughly 17" tall.

• Closed door depths can range from 15" to 18". Open-door depths will run from 42" to 45", but the standard width of over-the-range microwaves ensures that all models will have a similar swing-out radius. Expect over-the-range microwaves to extend beyond the surface of your cabinets. For a completely flush fit, explore built-in microwaves, which are designed to install directly into preexisting cabinetry. 

Built-in microwaves

Built-in microwaves are made to fit flush with cabinetry on all sides and, unlike over-the-range models, have no venting capabilities. 

• Interior space can range from 1.0 to over 2.0 cubic feet, with most landing between 1.2 to 1.6 cubic feet. 

• Widths align with standard cabinet widths, usually 24", 27" or 30".

• Depths range from roughly 20" to 25" with the door closed and 30" to 35" with the door open. Built-in microwaves often have a drop-down door and can be installed in a cabinet or under a counter.

How do I measure my current microwave dimensions?

Countertop microwaves

Measure the height, width and depth of your current microwave or the space on your countertop or shelves you want it to occupy. You should generally account for 1" of ventilation space between the microwave and the wall behind it and at least 3" of space from the edge of the counter to the open microwave door to avoid tipping, Also, try to put at least two feet between the microwave and the range.

Over-the-range and built-in microwaves

Measuring the height, width and depth of your existing microwave enclosure is more important than the measurements of your current appliance when it comes to over-the-range and built-in microwaves. Measure cabinet-to-cabinet, keeping in mind that it’s okay for over-the-range microwaves to drop below cabinets, as long as you retain 30" from the bottom of the microwave to the top of the stove. If you're installing the microwave oven near a left sidewall, make sure there is at least 6" of clearance between the wall and the microwave oven so that the door can open fully.

In addition to getting precise dimensions of your cutout, make sure there is space for ventilation per your manufacturer’s instructions. It’s important to note that built-in microwaves require professional installation.

What to consider other than a microwave’s size

Here are three more important considerations beyond dimensions.

The size of your family

A family of four or more will more than likely need a full-size microwave and may even consider a built-in microwave plus a countertop microwave depending on who is using it and what they’re using it for.

How you cook in your microwave

Are you using a microwave simply to re-heat items or pop the occasional bag of popcorn, or, do you plan on cooking casseroles and other larger dishes in it? If you’re cooking whole meals in the microwave, you might want to invest in a model with advanced features like select Whirlpool^® models with sensor or convection cooking.

The wattage you need

The more wattage, the quickler foods cook. Most recipes are written for 1,000 watts of power for optimal cooking results. If you cook a lot of frozen foods or food from scratch, you may want to aim for higher wattage.