Standard Microwave Dimensions: Which Type Fits
The three install types are not interchangeable sizes: a countertop unit is 20 to 24 inches wide, an over-the-range is 29.75 to 30 to match the range beneath it, and a built-in is sized by its trim kit at 24 to 30. What decides between them is the wall, not the microwave.
How big is a standard microwave?#
A microwave comes in three install types, and they are three different appliances that happen to heat food the same way: a countertop unit at 20 to 24 inches wide, an over-the-range at 29.75 to 30 inches so it lines up with the range beneath it, and a built-in at 24 to 30 inches framed by a trim kit. Comparing them on width alone is how a kitchen ends up with the wrong one. What actually decides is the wall — what is above the range, what hangs under the cabinets, and whether there is a cabinet to cut. The table below reads yours.
Standard microwave dimensions by configuration#
| Configuration | Width (in) | Height (in) | Depth (in) | Best for |
|---|---|---|---|---|
| Countertop | 20–24 | 12–14 | 15–20 | the simplest plug-and-go install |
| Over-the-range | 29.75–30 | 16–17 | 15–18 | saving counter space above the range |
| Built-in with trim kit | 24–30 | 17–19 | 22–25 | a flush cabinet or wall install |
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The wall you have, and the install type it takes#
Measure the gap above the cooktop, the height under the wall cabinets, and any tall-cabinet opening. Each install type answers to a different one of the three.
| What you measured | Install type it takes | The clearance that decides it |
|---|---|---|
| A 30-inch range with cabinets above it | Over-the-range (29.75–30 in wide) | It mounts with its top at 66 in from the floor and 13 to 18 in of gap above the cooktop — both are manufacturer figures, not preferences |
| Less than 13 in between the cooktop and the cabinet above | Not over-the-range | That gap is a requirement over a cooking surface; the answer is a countertop or built-in unit somewhere else in the kitchen |
| A counter run with 18 in under the wall cabinets | Countertop (12–14 in tall) | It needs 3 in of vent gap on the top and sides, so the body height is never the number to compare against the cabinet |
| A tall cabinet or wall opening in the 24–30 in band | Built-in with trim kit (17–19 in tall) | The trim kit frames the opening and covers the cut edge — the only class here where the cabinet is cut to the appliance |
| No wall cabinet above the range at all | Countertop or built-in, never over-the-range | An over-the-range unit hangs from the cabinet above it; with nothing to hang from, the class is off the table whatever the width |
Three install types are counted above, and comparing them on width alone is the error this page exists to prevent: an over-the-range unit is sized to the range, a built-in to its trim kit, and a countertop unit to nothing at all. The mounting figures are manufacturer requirements over a cooking surface, not conventions.
Installation clearances for a standard microwave#
- Countertop vent gap: 3 in in of clearance around a countertop microwave on the top and sides for venting.
- Over-the-range mounting height: 66 in in from the floor to the top of an over-the-range microwave, the standard cabinet mount.
- Cooktop-to-microwave gap: 13–18 in in the manufacturer wants between the cooktop and the bottom of an over-the-range microwave.
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Will your standard microwave fit? Clearances and door swing#
Which clearance you plan for depends on the install type. A countertop microwave needs about 3 inches around the vents and fits under an upper cabinet. An over-the-range unit mounts at about 66 inches with a 13-to-18-inch gap above the cooktop. A built-in with a trim kit slots into a cabinet, so the opening must match its 24-to-30-inch width and 22-to-25-inch depth exactly, with the trim kit closing the gap for a flush look. Measure for the specific install you have in mind — counter depth, wall height, or cabinet cutout — and confirm the venting path before you commit.
Standard microwave sizes by type: countertop, over-the-range, built-in with trim kit#
The three standard-microwave installs suit different kitchens. A countertop microwave, 20 to 24 inches wide and 12 to 14 inches tall at 15 to 20 inches deep, is the simplest — set it down and plug it in, leaving 3 inches for venting. An over-the-range microwave, 29.75 to 30 inches wide and 16 to 17 inches tall, doubles as a range hood and frees the counter. A built-in with a trim kit, 24 to 30 inches wide and the tallest at 17 to 19 inches, mounts flush in a cabinet or wall for a custom look at 22 to 25 inches deep. Pick countertop for flexibility, over-the-range or built-in for a finished kitchen.
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