How Wide Is a Microwave? | Typical Widths by Type

Most microwaves measure 18 to 30 inches wide overall, with countertop models at 21–25 inches and over-the-range units at 29–30 inches.

Microwave width is one of the first things to confirm before buying, because the size you need depends entirely on where you plan to put it. A countertop model has different space requirements than an over-the-range unit or a built-in. The good news is that most microwaves fall into a few predictable width ranges, so knowing which type you need narrows the search quickly.

Below is a breakdown of typical widths by microwave type, what to measure before you buy, and the mistakes that trip up most shoppers.

Microwave Width by Type: What to Expect

Each microwave style follows a different sizing standard, so start with the type that fits your kitchen setup.

• Countertop microwaves: These are the most common and usually measure about 21 to 25 inches wide, though some sources cite 18 to 24 inches as a typical range. They sit on a counter or shelf and need clearance around the vents, so the footprint matters more than the exterior width alone.
• Over-the-range (OTR) microwaves: Designed to mount above your stove, these units are almost always 29 to 30 inches wide. The 30-inch size is standard for aligning with a typical 30-inch range and cabinet opening. Compact OTR models come in around 24 inches wide.
• Built-in microwaves: These are installed into a cabinet or wall opening and commonly match cabinet widths of 24, 27, or 30 inches. A trim kit is usually required to close the gap between the microwave and the cabinet cutout.
• Microwave drawers: A newer style that slides open like a drawer, these come in 24-inch or 30-inch outside widths to fit standard cabinet sizes.

The single biggest takeaway: there is no universal microwave width. The range you need depends on the type you choose and the space you have.

How to Measure for a Microwave: Width vs. Cavity

When you look at microwave specs, the width listed is the exterior width, not the usable cooking space inside. Many shoppers confuse the two and end up with a unit that fits on paper but blocks a cabinet or leaves the door unable to swing open.

Here is what to measure before you buy:

• Cabinet opening: Measure the actual cutout width, not just the shelf space. Built-in and OTR units need the opening to match their 24, 27, or 30-inch width.
• Surrounding clearance: Microwaves need airflow for ventilation. Leave a few inches on the sides and rear for countertop models, and follow the manufacturer’s clearance specs for built-ins and OTR units.
• Door swing: A microwave that fits the opening can still fail if the door hits a wall or cabinet when opened. Account for the door’s full arc.
• Trim kit: For built-ins, the trim kit adds a frame around the unit. The cutout must match the microwave plus the trim kit dimensions, not just the microwave body.

If you are shopping for a countertop model and need a specific size, our roundup of 20-inch-wide microwaves covers the best units in that narrower footprint.

Common Sizing Mistakes (and How to Avoid Them)

Most microwave sizing problems come down to three recurring errors:

Assuming all microwaves fit a 30-inch opening. That width is standard for over-the-range models, but plenty of countertop units are far narrower. Always match the microwave type to the opening.

Measuring only the cabinet opening and ignoring clearance needs. Built-in units need room for ventilation and the trim kit, and over-the-range models need alignment with the range below and the cabinet above. An incorrect width can break that alignment entirely.

Overlooking the difference between exterior and interior dimensions. A 24-inch-wide built-in might have a cavity that fits a large casserole dish, or it might not. Check the cavity depth and width, not just the exterior, if you cook with big dishes.

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