Household Atlas
Household Atlas
Microwaves

Microwave Making Noise? Normal Hum vs. a Sound That Needs Service

Microwaves are not quiet machines. The magnetron hums, the fan whirs, relays click and food pops. A few sounds are worth acting on, and most of them come from the turntable, not the electronics.

By Luis Alberto Najar Isidro Updated 3-minute read 3 sources

Quick answer

Most microwave noise is normal: GE, Samsung and LG all say the magnetron and fan hum while it runs, and that clicking is the magnetron cycling or a relay. Grinding, clunking or frequent clicking usually comes from a dirty or misplaced turntable roller ring, which you can clean and reseat. A hum that is much louder than it used to be, or popping when heating plain water, needs service.

Difficulty
Easy DIY
Normal
Hum from the magnetron and fan; clicks from relays
Most common fixable noise
Dirty or misplaced turntable roller ring
Service
A hum much louder than before; popping with plain water
Never
Open the case or run the microwave empty
On this page

A microwave makes several sounds while it works, and the makers list most of them as normal. The useful question is whether a sound is new, louder than before, or tied to something you can see turning.

What each noise means

What you hear Most likely cause What to do
Low hum or buzz while heating Magnetron and vent fan (Samsung, LG) Nothing. A slight increase with age is normal (Samsung)
Thumping, clicking or humming on a low power level Magnetron cycling on and off (GE) Nothing
Clicks just after you press Start Relays switching (GE) Nothing
Faint hum when the microwave is idle Clock transformer (GE) Nothing
Grinding, clunking or frequent clicking as the plate turns Roller ring dirty or out of place, food on the turntable, or a dish too big (LG, Samsung) Clean and reseat the ring and plate (below)
Squeaking on a new microwave Shipping tape left on the turntable shaft (LG) Remove the tape
Rattling Filters not installed correctly (Samsung); something stored on top (LG) Reseat the filters; clear the top
Popping or snapping Fatty or watery food, or residue in a dirty cavity (Samsung) Clean the cavity, then test with water
Hum much louder than a month ago A change the makers say needs service Stop using it and request service

Why two microwaves sound different

GE points out that microwaves make different sounds from model to model, and even depending on where they are installed: an over-the-range microwave makes different noises from one on the counter. Some modes add their own sounds:

  • Defrost. LG explains that during defrost the fan keeps circulating air while the magnetron switches on for a short time and then off, so the hum comes and goes. That is how it thaws food without cooking the edges.
  • Convection or combination cooking. On models with this feature, GE says the convection element and fan cycle continuously alongside the hum of the magnetron and its fan.
  • Age. Samsung says a slight increase in volume as the microwave gets older is normal. A sudden jump is not.

So compare a noise with how your own microwave sounded before, not with a friend’s.

Check it in this order

  1. Listen on full power, then on a lower setting.Safe check

    A rhythmic thump or click that only appears below High is the magnetron cycling, which GE describes as normal.

  2. Clean the turntable, roller ring and track.Safe check

    Unplug the microwave, lift out the glass plate and the roller ring, wash them, wipe the track underneath, and put the ring and plate back so they sit flat. LG and Samsung both name food particles and a misplaced ring as causes of clunking and clicking.

  3. Use a dish that turns freely.Safe check

    LG lists oversize cookware as a cause of clunking, and notes that a heavy load can stop the tray turning smoothly.

  4. Test with a cup of water.Safe check

    Samsung’s test: clean the microwave and heat a bowl or glass of water. If it still pops, request service. Never run the microwave empty; Samsung says that causes popping and can damage it.

  5. Anything else goes to a technician.Technician

    A hum that has become much louder, a grinding noise that cleaning did not fix, or any burning smell needs service. The inside of a microwave holds high-voltage parts that stay dangerous after it is unplugged, so do not open the case.

Sparks, smoke or a burning smell mean stop. Press Stop, keep the door closed and unplug the microwave. Arcing usually comes from metal in the cavity or a damaged part; see the sparking section of our microwave guide.

Repair or replace?

Turntable parts and filters are cheap, user-replaceable parts. A failing magnetron, fan motor or transformer is a technician repair. The repair or replace calculator weighs the quote against the microwave’s age. If the microwave also runs without heating, start with a microwave that is not heating.

Bottom lineHumming, clicking on low power and the odd pop are normal. Grinding, clunking and frequent clicking usually mean the turntable ring needs cleaning or reseating. A hum that got much louder, popping with plain water, sparks or a burning smell mean stop using it and call for service.

Frequently asked questions

Is it normal for a microwave to hum?

Yes. Samsung says a low humming or buzzing sound is normal while the microwave runs, mostly from the magnetron when it heats and from the vent fan, and that it is normal for the volume to increase slightly with age. If it is much louder than it was a month ago, Samsung recommends requesting service and recording the noise for the technician.

Why does my microwave make a thumping or clicking noise on low power?

GE explains that at any power level below High the magnetron cycles on and off to reduce the power, and that cycling causes a dull thumping, clicking or humming noise. It is normal.

Why is my microwave grinding or clunking?

LG lists three causes of clunking: cookware too large for the cavity, a rotating ring installed incorrectly, and food on the roller and turntable. Samsung adds that frequent clicking means the track and roller ring may need cleaning or repositioning. Clean them, reseat the ring and glass tray, and test again.

Why does my microwave hum when it is not in use?

GE says the transformer for the clock gives off a slight humming sound, usually not noticed. A steady, faint hum when the microwave is idle is not a fault.

Can I run a microwave empty to test the noise?

No. Samsung warns not to run the microwave completely empty, because it causes popping noises and can damage it. Test with a cup or bowl of water instead.

Sources

  1. Microwave - Normal Operational Characteristics GE Appliances
  2. Samsung microwave is making weird noises Samsung US
  3. LG Micro-wave - Noises LG USA Support

First published October 31, 2026. Last reviewed October 31, 2026. Spot an error? Tell us and we will check it against the source.

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