No, microwaves vary in size based on capacity and type, ranging from compact countertop units to larger over-the-range or built-in models.
Your microwave just stopped heating. Or perhaps you want to upgrade your kitchen for a fresh look. You stand in the appliance aisle or scroll through a webpage, and a question hits you. Are All Microwaves The Same Size? You might assume a standard box fits a standard hole, but that assumption leads to return hassles and installation headaches.
Microwaves differ wildly in height, width, and depth. A compact countertop model will not fill the gap left by a built-in unit. Even over-the-range models, which appear uniform, have subtle differences that mess up your tile work or cabinet alignment. You need precise numbers before you spend a dime.
This guide breaks down every dimension you need to check. We will cover the standard sizes for each microwave style, how to measure your space accurately, and the hidden clearance rules that prevent fires and overheating.
Microwaves Are Not One Size Fits All
Appliance manufacturers build microwaves to fit specific user needs. A college student needs a tiny box for a dorm room. A family of five needs a machine that defrosts a whole turkey. These different needs dictate the physical footprint of the unit.
Capacity often dictates size, but not always. Two microwaves might both offer 1.5 cubic feet of internal cooking space, yet one could be two inches wider due to the control panel design. External dimensions matter more than internal volume when you fit the appliance into a cabinet or on a shelf.
Understanding the three main categories helps you narrow down the search. We have Countertop, Over-the-Range (OTR), and Built-In models. Each category follows its own set of sizing rules.
Standard Dimensions By Microwave Type
You can find common ranges for each type of microwave. While outliers exist, most brands stick to these general buckets to match standard American cabinet sizes.
Countertop Models
Countertop units offer the most variety. You can find tiny cubes and massive powerhouses in this category. Manufacturers categorize them by size: Compact, Mid-Size, and Full-Size.
Compact models usually stick to widths under 20 inches. These work well for reheating coffee or a slice of pizza. Mid-size units often land between 21 and 24 inches wide. Full-size counter models can stretch up to 24 or even 25 inches. Depth varies heavily here. Some units have a “bump out” in the back for the fan, adding two inches to the listed depth.
Over-The-Range (OTR) Units
These units double as range hoods. Because standard stoves measure 30 inches wide, almost all OTR microwaves measure roughly 29.8 to 30 inches wide. This makes swapping them easier than other types.
However, height creates problems. Older OTRs were often shorter. Newer models tend to be taller. If you have a tiled backsplash running up to your current microwave, a taller new unit might not fit without removing tiles.
Built-In Microwaves
Built-ins sit inside a cabinet or wall recess. They often use a trim kit to make the unit look flush with the cabinetry. The microwave itself might be small, but the trim kit forces it to fit a 27-inch or 30-inch cabinet opening.
Drawer microwaves also fall into this group. They install below the countertop and pull out like a standard drawer. Most drawers require a 24-inch or 30-inch cabinet width.
Quick Reference Size Chart
Use this table to identify which category your current unit falls into. This data helps you set a baseline for your replacement search.
| Microwave Type | Standard Width | Typical Height |
|---|---|---|
| Compact Countertop | 15″ – 19″ | 10″ – 11″ |
| Mid-Size Countertop | 19″ – 22″ | 11″ – 13″ |
| Full-Size Countertop | 23″ – 25″ | 13″ – 15″ |
| Over-The-Range | 29.8″ – 30″ | 15″ – 17″ |
| Built-In (With Trim) | 27″ or 30″ | 17″ – 22″ |
| Drawer Style | 24″ or 30″ | 15″ – 16″ |
| Commercial | 20″ – 22″ | 12″ – 14″ |
Are All Microwaves The Same Size? | Detailed Breakdown
Even if you stick to one type, you cannot assume a perfect match. The question Are All Microwaves The Same Size? gets a firm “no” even within sub-categories. Design choices impact the exterior dimensions significantly.
Control panels add width. Some brands place controls on the bottom to save horizontal space, while others put them on the right side. This design choice changes the width by three to four inches. If you have a tight “appliance garage” or cabinet cubby, that width difference prevents the door from opening.
Handle depth often surprises buyers. The spec sheet usually lists the depth of the chassis (the box). It might list the depth with the door. But the handle protrudes another two inches. If your microwave sits near a pantry door or a drawer, that handle might block other kitchen functions.
Feet height also varies. Countertop models sit on small legs to allow airflow underneath. Some legs are half an inch; others are nearly an inch. This affects the total height clearance if you slide the unit under a low upper cabinet.
How To Measure Your Space Correctly
You need accurate numbers to avoid return shipping fees. Do not rely on the volume (cubic feet) printed on the front. Get a stiff metal tape measure. Cloth tapes stretch and flex, leading to bad data.
Measuring The Width
Measure the width of the cutout, not the old microwave. Your old unit might be smaller than the opening. You want to know the maximum space available. Measure at the front and the back of the cabinet. Walls are rarely perfectly square. Use the smaller of the two numbers as your maximum width.
Measuring The Height
Check the vertical opening from the shelf to the cabinet above. For OTR units, measure from the bottom of the upper cabinet to the top of the stove backsplash. Safety codes usually require a specific distance between the stovetop and the bottom of the microwave.
According to GE Appliances installation resources, you generally need at least 66 inches from the floor to the top of the microwave for proper over-the-range clearance. Always check the specific manual for your model.
Measuring The Depth
Depth causes the most issues. Measure from the back wall to the front edge of the cabinet. Remember to account for the plug. The plug adds about one to two inches of required depth behind the unit. If you buy a microwave that matches the exact depth of your cabinet, it will stick out once you plug it in.
Clearance And Airflow Requirements
Microwaves generate heat. They need to breathe. If you stuff a countertop microwave into a tight cabinet with zero gaps, it will overheat and shut down. It might even fail permanently.
Manufacturers list required clearances in the user manual. A common rule of thumb involves leaving three inches of space on the sides and top, plus one inch in the rear. Built-in microwaves utilize trim kits to channel air out the front, which eliminates the need for side gaps inside the cabinet. Do not try to “build in” a standard countertop unit without a proper trim kit. It creates a fire hazard.
Understanding Cubic Feet Vs External Size
Shoppers often confuse internal capacity with external size. Capacity refers to the cooking chamber volume. It is measured in cubic feet. Common sizes range from 0.5 to 2.2 cubic feet.
A 1.2 cubic foot microwave usually takes up less counter space than a 2.0 cubic foot model. However, high-wattage compact inverters can pack a lot of power into a small frame. Do not assume a small footprint means weak cooking power.
Also, the turntable size matters. If you frequently reheat dinner on large square plates, bring a plate to the store. Test it. A 1.5 cubic foot model might have a wide but shallow cavity that fits the plate, while a taller 1.5 cubic foot model might not.
The Importance Of Trim Kits
If you want that sleek, integrated look, you need a trim kit. A trim kit consists of a frame and ductwork that surrounds the microwave. It covers the gaps between the appliance and the cabinet wood.
Trim kits are model-specific. You cannot buy a generic “30-inch trim kit” and expect it to fit a Panasonic microwave. The screw holes and air ducts align only with specific models. When you buy a built-in microwave, buy the matching trim kit at the same time.
Trim kits usually come in two standard widths: 27 inches and 30 inches. Note that the microwave inside is often the same size for both kits. The 30-inch kit just has a wider metal frame to cover a wider cabinet opening.
This table outlines what cabinet cutout sizes you typically need for these kits. Always verify with the specific spec sheet before cutting wood.
| Trim Kit Width | Min Cabinet Width | Min Cutout Depth |
|---|---|---|
| 24″ (Drawer) | 24 1/8″ | 23 1/2″ |
| 27″ Kit | 27 1/8″ | 21″ – 24″ |
| 30″ Kit | 30 1/8″ | 21″ – 24″ |
| OTR (Standard) | 30″ | 12″ – 14″ |
| OTR (Slim) | 30″ | 12″ – 14″ |
Replacing An Over-The-Range Microwave
Swapping an OTR unit involves more than just dimensions. You must consider the mounting bracket. Every manufacturer uses a different back-plate. You will likely need to remove the old metal plate bolted to the wall and install the new one that comes with your new microwave.
The bolt holes in the upper cabinet also vary. The screws that hold the front of the microwave up rarely align from one brand to another. You will probably need to drill new holes in your cabinet shelf. Since most over-the-range microwaves are 30 inches wide, the width is rarely the issue; it is the mounting hardware that demands effort.
Wattage And Size Correlation
Size often correlates with power. Larger microwaves generally offer higher wattage. A 700-watt compact unit struggles to pop popcorn evenly. A 1200-watt family-size unit boils water rapidly.
If you downsize to save counter space, you likely sacrifice speed. You will need to adjust your cooking times. If a recipe calls for 2 minutes on high, a smaller, lower-wattage unit might need 3 minutes. Check the wattage rating on the sticker inside the door or on the back.
Cabinet Depth Issues
Standard upper cabinets measure 12 inches deep. Most microwaves are deeper than 12 inches. This means the microwave will stick out. This is normal for countertop units placed on a shelf. However, ensure the feet sit firmly on the shelf. If the front feet hang over the edge, the unit will tip forward when you open the door.
For built-ins, standard base cabinets are 24 inches deep. This accommodates almost any microwave. The challenge arises with “pantry” cabinets or wall towers, which might only be 18 inches deep. Always check the unit’s depth requirement against your actual shelf depth.
Door Swing Clearance
The hinge side of the microwave creates a blind spot. If you place the microwave directly against a wall on the left side (since most hinge on the left), the door might not open 90 degrees. You need a few inches of clearance on the hinge side so the door can swing wide enough for you to remove hot dishes safely.
Some newer models feature “zero clearance” hinges that open flush with the side of the unit. These work great in tight corners. Check the product description for this feature if your space is restricted.
When To Call A Pro
You can handle a countertop swap easily. OTR installations require two people due to the weight. However, if you need to cut cabinetry or adjust electrical outlets, call a professional. Dedicated circuits are safer for microwaves. If your old unit tripped the breaker often, a new, more powerful unit will make the problem worse. An electrician can run a new line to handle the load.
Modifying Cabinets For Fit
Sometimes you find a microwave you love, but it is half an inch too tall for the opening. Trimming the cabinet trim is an option. A carpenter can shave down the face frame to create space. Alternatively, you can remove a light rail or decorative strip from the bottom of an upper cabinet to gain height.
Never modify the microwave feet. Removing the feet to gain height blocks airflow and voids the warranty. It creates a serious fire risk.
Final Thoughts On Sizing
So, Are All Microwaves The Same Size? Definitely not. The variety ensures you can find a unit for any kitchen, but it also mandates careful measuring. Ignore the marketing photos. Focus on the height, width, and depth specifications listed in the user manual.
Measure your space twice. account for the plug depth. Check for airflow gaps. If you tackle an OTR installation, prepare to change the mounting bracket. With the right numbers in hand, you can buy with confidence and slide that new appliance right into place.