What you need to know before you start

Replacing an over-the-stove microwave is a job you can do yourself if you are comfortable working at height and handling electrical connections, but it requires careful planning. The unit is heavy, mounted above your stove, and wired into your home's electrical system. You will need to turn off power at the breaker, disconnect the old unit, remove the mounting bracket, install a new bracket, and wire in the replacement. Most of the work is straightforward, but the electrical connection and the weight of the unit mean you should have a helper and may want to call a licensed electrician for the wiring if you have never done it before.

The entire job typically takes two to four hours if you work methodically and have a second person to help support the unit. If you call an electrician to handle the wiring, add another hour or two to the timeline and budget for their service call.

Key Takeaways

  • Turn off power to the microwave at the circuit breaker before you touch anything electrical or remove the old unit.
  • You will need a helper to support the weight of the microwave while you disconnect it and install the new one, since these units typically weigh 60 to 80 pounds.
  • The mounting bracket bolts to the wall studs above your stove, and you must use the correct fasteners for your wall type to prevent the new unit from falling.
  • The electrical connection involves a three-prong plug or hardwired connection depending on your model; if you are unsure about wiring, hire a licensed electrician rather than guessing.
  • Measure the space carefully before you buy a replacement, because over-the-stove microwaves come in standard widths (30 inches is most common) but depth and height vary.

Measure the space and choose the right replacement

Before you buy a new microwave, measure the width, height, and depth of the space where the old one sits. Most over-the-stove models are 30 inches wide, but some are 24 or 36 inches. The depth and height matter just as much, because the new unit must fit in the same footprint and clear your stovetop. Write down all three measurements and bring them with you or check them against the product specs online.

Check whether your current microwave is plugged into an outlet or hardwired into the electrical system. If it is plugged in, you will see a cord disappearing into the wall or cabinet. If it is hardwired, there will be no cord visible. This matters because you need to buy a replacement that matches your setup, or you will have to rewire it. Most over-the-stove microwaves can be either plugged or hardwired, but the installation method differs.

Also note the mounting bracket type on your old unit. Some brackets bolt directly to wall studs, while others use a rail system. Take a photo of the bracket before you remove the old microwave so you know what you are working with.

Turn off power and remove the old microwave

Go to your electrical panel and find the breaker that controls the microwave circuit. It is usually labeled, but if you are not sure, flip the breaker and ask your helper to test the microwave to confirm it is off. Once the power is off, do not turn it back on until the new unit is fully installed and wired.

If the microwave is plugged in, unplug it from the outlet. If it is hardwired, you will see wire connectors inside the unit where the power enters. Do not touch these yet—wait until you have the old unit down and can work safely on a table.

Open the cabinet or wall space above the microwave to see the mounting bolts. These usually run through the top of the unit into the bracket behind it. You will need a socket wrench or adjustable wrench to remove them. Have your helper support the weight of the microwave from below while you loosen the bolts. Once the bolts are loose, carefully lower the unit onto a sturdy table or cart. Do not let it hang by the electrical connections.

If the microwave is hardwired, disconnect the wires now that the unit is on a table. You will see three wires—usually black (hot), white (neutral), and green or bare copper (ground)—connected with wire nuts or a terminal block. Untwist or unscrew these connectors and separate the wires. Take a photo of the wire arrangement before you disconnect them, so you know how to reconnect the new unit.

Remove the old bracket and prepare the wall

Once the microwave is off the wall, you can remove the mounting bracket. It is bolted to the wall studs behind your cabinet or directly to the wall. Use your wrench to remove these bolts and carefully pull the bracket away. If the bolts are stuck, spray them with penetrating oil and wait a few minutes before trying again.

Inspect the wall studs where the bracket was mounted. If they are solid and not damaged, you can reuse the same bolt holes for the new bracket. If the holes are stripped or enlarged, you may need to drill new holes slightly higher or lower. Check the new microwave's bracket to see where the bolt holes should be, and mark them with a pencil before you drill.

If you are drilling new holes, use a drill bit slightly smaller than the bolts you will use, and drill straight into the stud. Do not drill into drywall alone—the microwave is too heavy to hang from drywall fasteners. If the studs are not where you need them, you will have to install a horizontal support beam (called a ledger board) between the studs to anchor the bracket. This is a job for a carpenter or electrician if you have not done it before.

Install the new mounting bracket

Position the new bracket against the wall studs, aligning the bolt holes with the holes you marked or the existing holes from the old bracket. Use the bolts, washers, and nuts that came with your new microwave—do not reuse old hardware, as it may not be the right size or strength. Insert the bolts through the bracket into the studs and tighten them firmly with your wrench. The bracket should not move or flex when you push on it.

Check that the bracket is level using a level tool. If it is tilted, loosen the bolts, adjust the bracket, and retighten. A tilted bracket can cause the microwave to sit unevenly and may stress the mounting hardware over time.

Once the bracket is find, test it by hanging on it gently with your hands. It should feel solid and immovable. If it shifts or creaks, tighten the bolts further or check that they are in the studs and not just drywall.

Wire the new microwave and mount it

Before you lift the new microwave onto the bracket, prepare the electrical connection. If your old microwave was plugged in and the new one is also a plug-in model, you can straightforward plug it in once it is mounted. If it is hardwired, you need to connect the wires now, while the unit is still on the table.

Strip about half an inch of insulation from the end of each wire on the new microwave using a wire stripper. Match the wires to the ones you photographed from the old unit: black to black (hot), white to white (neutral), and green or bare copper to green or bare copper (ground). Twist each pair of wires together clockwise, then screw a wire nut onto each connection and tighten it by hand until it is snug. Gently tug on each wire to make sure the connection does not slip. If you are not confident in your wiring, stop here and call a licensed electrician to complete this step.

Once the wires are connected (or if the unit is plug-in and you will plug it in after mounting), have your helper support the microwave while you lift it onto the bracket. Align the mounting holes on the microwave with the bolt holes on the bracket, and insert the bolts. Tighten them firmly but do not over-tighten, as you can crack the microwave's casing. The unit should sit flush against the wall with no gaps.

If the microwave is plug-in, plug it into the outlet now. If it is hardwired, the wires should be tucked neatly into the wall cavity behind the unit. Turn the breaker back on and test the microwave by setting it to run for a few seconds. If it powers on and the light comes on, the installation is complete.

Test and adjust after installation

Once the microwave is mounted and powered, run a full test. Set it to high power for 30 seconds with a cup of water inside to make sure it heats. Check that the turntable spins, the light comes on, and the buttons respond. If anything does not work, turn off the breaker when ready and check your wiring connections.

Look at the clearance between the microwave and your stovetop. There should be at least 13 to 15 inches of space to allow steam and heat to escape. If the microwave is too close to the stove, it can overheat and fail prematurely. If you have less than 13 inches, you may need a different model or a professional to adjust the bracket height.

Check that all the bolts are still tight after 24 hours of use. The weight of the microwave can sometimes cause bolts to settle slightly, so a quick check the next day is a good safety measure.

When to call a professional

Call a licensed electrician if you are unsure about the wiring, if your old microwave was hardwired and you have never worked with electrical connections, or if the new microwave requires a different circuit than the old one. Electricians can also help if the wall studs are not where you need them or if you need to install a support beam.

Call a carpenter if the mounting bracket does not align with the studs or if you need to reinforce the wall to support the weight. A structural problem now is cheaper to fix than a microwave falling onto your stove later.

If the microwave does not power on after installation, do not assume the unit is broken. Check that the breaker is on, that the plug is fully inserted (if it is a plug-in model), and that the wiring connections are tight. If those are all correct and it still does not work, the unit may be defective and should be returned to the retailer.

Frequently Asked Questions

Can I install a microwave that is a different size than my old one?

Only if it fits the space. Over-the-stove microwaves come in standard widths (24, 30, or 36 inches), and you must match your cabinet opening. If you want a different size, you may need to modify the cabinet or the mounting bracket, which is a job for a carpenter. Depth and height also matter—measure carefully before you buy.

What if there is no outlet behind my microwave?

If the old microwave was hardwired, the new one should be too. If you want to switch to a plug-in model, you will need an electrician to install an outlet in the wall cavity behind the microwave. This is not a DIY job because it involves running new electrical wire through your walls.

How much weight can the mounting bracket hold?

The bracket is rated for the weight of the microwave it comes with, usually 60 to 80 pounds. Do not use a bracket from a lighter microwave to mount a heavier one, and do not hang anything else from the bracket. If the bracket feels loose or the microwave shifts, stop using it and have an electrician inspect the installation.

Do I need to turn off the breaker while the microwave is running?

No. Turn off the breaker only when you are working on the electrical connections or removing and installing the unit. Once the microwave is mounted and wired, the breaker should stay on so the unit works normally.

What should I do with my old microwave?

Most retailers that sell microwaves will haul away your old one for free or a small fee when they deliver the new one. If you are installing it yourself, check with your local waste management or recycling center about how to dispose of it. Microwaves contain materials that should not go in a regular trash bin.