Standard Microwave Sizes by Type and Width

What standard microwave size really means

Microwave sizes are not one universal dimension. In the same way an appliance maker plans a kitchen line around cabinet openings, a microwave is described by its installation type and its exterior dimensions. The three common groups are countertop, over-the-range, and built-in. Drawer models are a fourth option for low placement. Each type answers a different question: where does the oven sit, and what does it need to fit?

The microwave oven became a common kitchen appliance after the first countertop model appeared in the late 1960s. Since then, manufacturers have grouped models by where they go in the kitchen, not by a single industry-wide size chart. That is why you should choose by installation type first, then by the dimensions of the space you have.

• Countertop models sit on a work surface and are the easiest to move or replace.
• Over-the-range models mount above the cooking surface and usually include ventilation.
• Built-in models are installed into a wall or cabinet opening, often with a trim kit.
• Drawer models slide out horizontally from under a counter or inside a base cabinet.

Measure the opening before you pick a size

The first step is to measure the actual space. For a countertop model, that means the counter depth and the clearances above and beside the microwave. For an over-the-range model, measure the width of the cabinet opening, the distance from the range top to the cabinets, and the depth available. For built-in and drawer models, measure the rough opening in the cabinet, including any trim that will be used.

Leave room for air to move around the microwave and for the door to open fully. A microwave with no turntable may require you to rotate the dish by hand during cooking, as the FDA suggests in its food safety guidance, so make sure you can reach around the appliance comfortably. The full measuring process is covered in how to measure for a microwave.

Countertop microwave sizes

Countertop microwaves are the most common type and the easiest to shop for. They sit on a work surface and come in a broad spread of capacities, from small models that fit in a dorm room or RV to large units that hold big dishes. Because they do not need a cabinet opening, their size is mostly a matter of counter space and clearance.

If you cook for one or two, a compact countertop model may be enough. If you routinely heat large platters or use rectangular containers, check the interior dimensions before you settle on a capacity. A larger interior usually means a larger footprint, so compare both the exterior size and the microwave interior dimensions and plate size before ordering.

• Small or compact models work well in tight kitchens, offices and RVs.
• Mid-size countertop models are the most popular everyday choice.
• Large countertop models provide more plate space but take up more counter area.

Over-the-range microwave sizes

Over-the-range microwaves are designed to take the place of a range hood above your cooking surface. They are sized to fit the same sort of cabinet widths as standard ranges, and they include ventilation for smoke and steam. Because they are mounted at eye level, they free up counter space and keep the cooking surface clear.

The main fit challenge is that the mounting height has to work with the range below and the cabinets above. When replacing an existing over-the-range model, use the same width and verify the venting path before you order. See the over-the-range microwave buying guide for models grouped by specs, and review over-the-range microwave height for clearance considerations.

Built-in and trim kit sizes

Built-in microwaves are made to slide into a wall, cabinet, or column opening. The surrounding trim kit makes the fit look finished and hides gaps. Because the opening is fixed, you need the cabinet dimensions first. Some appliance makers offer built-in microwave families alongside their other built-in appliances, so the width of the opening can match the overall kitchen plan.

A countertop microwave cannot simply be placed into a built-in opening unless the manufacturer says it is compatible with a trim kit. Warm air needs an escape path, and the trim must be designed for that specific model. Learn more about microwave trim kit compatibility and the differences between built-in and countertop microwaves.

Drawer microwave sizes

Drawer microwaves mount under a counter or in a low cabinet and open outward on a drawer mechanism. They are useful in islands and in kitchens where an eye-level oven would obstruct a window or backsplash. Their sizing is tied to the base cabinet opening, so the same measure-first approach applies.

Confirm the drawer front style and minimum cabinet depth before purchase. A drawer model changes how you load and unload food, so compare the opening height as well as the interior capacity. The drawer microwave buying guide can help you compare options, and microwave drawer installation explains the cabinet requirements.

Choosing for your kitchen

Start with the place the microwave will live. If you are replacing an old countertop unit, measure that footprint. If you are replacing an over-the-range unit, measure the mounted width and the cabinet above. If you are putting a microwave into new cabinetry, choose the appliance and the trim kit at the same time, because the cutout is made for that combination.

After you know the type, decide the capacity you actually use. Larger interiors accept big platters, but they also need more exterior space. For day-to-day reheating, a mid-size countertop model is often enough. The guides below group microwaves by capacity, power and installation type, so you can compare models that will fit. In the United States, the FDA also oversees microwave ovens as radiation-emitting electronic products, so follow the manufacturer instructions and keep the door seals clean after installation.

What to pick for your use

Questions

Do all microwave brands use the same size labels?

No. Terms like compact, mid-size, full-size, over-the-range and built-in are useful starting points, but they are not universal standards. Always compare the manufacturer's stated width, height and depth against your actual opening.

Can a countertop microwave be installed above the range?

No. Unless a model is specifically built and rated for over-the-range mounting, it should not be used in that position. Over-the-range units include ventilation, mounting hardware and clearances designed for that installation.

Should I choose by exterior size or interior capacity?

Check both. Exterior size tells you whether the microwave will fit in your space. Interior capacity, usually listed in cubic feet, tells you how much food and what size plates the oven can hold. A large capacity is useful only if the exterior fits.

What if the opening is narrower than the microwave I want?

Choose an appliance that fits the opening. A trim kit can hide gaps only when the kit is designed for that specific model. For built-in installations, confirm the rough opening dimensions before ordering.

Do built-in microwaves need a special outlet?

Built-in and over-the-range microwaves often need a dedicated circuit and a properly located receptacle. Check the manufacturer's electrical requirements and your local wiring rules before installation. Learn more in microwave electrical requirements.