How Big Is 1.5 Cubic Feet Microwave? | Real Fit Facts

A 1.5-cubic-foot microwave holds roughly 1.5 cubic feet of interior cavity space and typically measures about 21–24 inches wide, 12–15 inches tall, and 16–19 inches deep outside.

When a microwave is labeled 1.5 cu. ft., that number describes the oven cavity’s interior volume — the space where your food goes — not the appliance’s exterior footprint. It’s a mid-size capacity, a common choice for small families or anyone who cooks more than just convenience meals. Before you buy one, the dimensions that actually decide whether it fits your kitchen are the exterior ones, and those vary noticeably between models.

What “1.5 Cu. Ft.” Actually Measures

Manufacturers calculate capacity by measuring the interior cavity — width times height times depth — and converting that to cubic feet. So a 1.5-cu.-ft. microwave gives you about 1.5 cubic feet of usable space for plates, casserole dishes, and bowls. It does not mean the microwave’s outer shell measures 1.5 cubic feet.

To get a sense of the real footprint, look at two official LG spec sheets. The LG MSWN1590L countertop model lists exterior dimensions of 21.41 inches wide, 12.13 inches high, and 17.00 inches deep, with a cavity of 15.43 x 10.31 x 15.98 inches and a 14.2-inch turntable. The LG LMC1575 over-the-range model shares the same cavity size but different exterior measurements. In general, published exteriors for 1.5-cu.-ft. units cluster around 21.4–24.8 inches wide, 12.1–15 inches high, and 16.5–19.3 inches deep.

Because footprints vary by brand and model, capacity alone won’t tell you whether a unit fits your counter or cabinet cutout. You have to compare the appliance’s exterior dimensions against your available space.

How To Check If One Will Fit Your Kitchen

The right way to size a microwave is to measure your space and compare it to the unit’s exterior dimensions — never rely on the capacity figure alone. Grab a tape measure and check three things:

• Width, height, and depth of the opening. For countertop placement, measure with the door closed, then account for airflow around the unit. Maytag’s installation guidance recommends leaving about 1 inch of ventilation space between the microwave and the wall behind it.
• Door-open depth. The door swings out, and the microwave’s total depth with the door open is far larger than its closed depth. That extra reach can block adjacent cabinets or walkways.
• Turntable and cavity size. If you regularly heat large platters or tall mugs, check the cavity height and turntable diameter, not just the cubic-foot rating. A wide platter can still be too big for a shallow cavity even when the volume looks generous.

For over-the-range or built-in models, measure the cutout space precisely and verify the manufacturer’s ventilation and clearance instructions before installation. These units need specific airflow allowances that don’t apply to countertop models.

Fitting A 1.5-Cu.-Ft. Microwave On A Counter

For countertop placement, the exterior measurements are your go-to numbers. A typical 1.5-cu.-ft. countertop unit needs a spot roughly 22 inches wide, 17–19 inches deep, and 13 inches tall, plus clearance behind it for ventilation. If your counter is shallow — many are only 24 inches deep — a model on the deeper end of the range might overhang the edge. The LG MSWN1590L example runs about 17 inches deep closed, which fits comfortably on most standard counters.

Door swing matters just as much as the closed footprint. A microwave sitting near a corner or beside a tall cabinet needs room for the door to open fully so you can load and unload dishes. If your kitchen is tight, look for a model with a door that opens within your available clearance.

Common Sizing Mistakes To Skip

Three errors trip up most buyers. The first is reading cubic feet as an exterior measurement — it’s interior volume, and a 1.5-cu.-ft. oven is considerably bigger on the outside than on the inside. The second is forgetting to measure the door-open depth, which can be several inches larger than the closed depth. The third is ignoring ventilation clearance; without that inch of airflow behind the unit, performance and longevity can suffer.

Also bear in mind that not all 1.5-cu.-ft. microwaves share a footprint. Two units with identical capacity can differ by an inch or more in width and depth. Always verify the specific model’s exterior spec sheet before you commit. If you’re comparing over-the-range options and want a shortlist of models that fit standard cutouts, our tested roundup of the best 1.5 cu ft over the range microwaves covers the standouts.

Does Capacity Affect What Fits Inside?

Yes, but not the way you might assume. A 1.5-cu.-ft. cavity is roomy enough for most dinner plates, casserole dishes, and even a small roasting pan. Still, the cavity’s shape and the turntable’s diameter decide what actually fits. A tall coffee mug might clear the ceiling in one model and not another, and a square baking dish can catch the walls in a narrower cavity even when the volume is identical.

The practical rule: match the turntable diameter to your largest everyday dish, and check the cavity height if you regularly heat drinks in tall mugs or stack plates. For a small family or frequent home cooks, this capacity is a solid middle ground — big enough for serious reheating and defrosting without dominating the counter.