A microwave making noise is usually a microwave working. GE, LG, Samsung and Whirlpool all describe a hum or buzz from the magnetron and its cooling fan as normal, and GE and Sharp expect clicks at lower power. Popping from fatty food and a fan that keeps going after the door opens are on the normal lists too.
A few sounds are different. Sparks and crackling from inside the cavity are arcing, which the makers say to stop at once, and a sudden new loud noise is one LG and Samsung send to service.
Below, every sound comes with the maker's explanation from its support pages and use and care manuals, sorted by the moment you notice it: while cooking, when the plate turns, after the cycle, with the oven off, and when the beeper will not stop.
Is it normal for a microwave to make noise?
Yes. A microwave hums whenever it heats. LG says a microwave oven generates vibration noise "of about 45 to 50 decibels (dB) during the process of producing high frequency waves", and that "The sound is normal".
GE adds that microwaves "make different sounds from model to model", and that a model over your range "will make different noises than one on your counter."
Samsung says most microwave sounds "are normal and should not be a cause of concern", and that the food and other material inside are typically what you are hearing. It also says it "is also normal for the volume of the microwave to slightly increase with age."
What sounds does a microwave make while it is cooking?
A cooking microwave hums, buzzes, clicks and thumps, and the food inside pops and sizzles. The makers trace these to the magnetron switching on and off, the cooling fan, relays, and fat or water in the food.
A hum or buzz from the magnetron and the cooling fan
Whirlpool says "It is normal for the unit to produce a humming noise during operation", and that the hum "is the result of the power supply switching the magnetron on and off." Its buzzing page gives the same cause for a buzz.
Samsung calls the sound "a low humming or buzzing sound", most commonly from "magnetron oscillation (when the microwave is heating), the vent fan running, or both." LG says "The Magnetron will hum when in operation", and that a hum at the beginning of a cycle is normal.
Clicks and a dull thump at lower power levels
Below full power, the magnetron does not run all the time. GE says that at any power level other than High, "the magnetron cycles on and off to obtain the lower power. This cycling causes a dull thumping, clicking, or humming noise."
Sharp's microwave drawer manual says the same: below 100% power "you may hear the magnetron cycling on and off."
GE also says "It is normal to hear clicks or relays after starting the cycle", even before the oven starts running. LG lists the door latch as a second source of clicks.
Popping and sizzling from the food
GE says popping "is typically a normal sound and not an indication of a problem with the appliance." Fatty food "will pop and sizzle as it heats up", and covering the container reduces it. Potatoes build up pressure under the skin, so GE says to pierce them first.
Samsung names steak, tomato sauce, potatoes and popcorn, and says leftover food in a dirty microwave pops too. GE says spills cause popping, and asks you to clean them up as soon as they happen.
Convection and combination cooking
Combination models add a second set of sounds. GE says "The cycling of the convection element and fan will alternate continuously with the hum of the magnetron and the fan."
During defrost, LG says its fan circulates air while the magnetron runs "for a little time, then shut off while the fan continues to circulate the air around the food", so the sound comes and goes.
Why is my microwave making a loud humming noise?
A loud hum is normal magnetron and fan noise unless it has grown much louder or arrived suddenly. Samsung and LG both draw the line at a change: louder than last month, or a sudden loud noise.
Samsung's test is the past month: "If the volume of this noise is significantly louder than it was a month ago", request service, and record the noise for the technician. LG says "If a sudden loud noise occurs, a professional service inspection may be required."
Before that call, LG lists three checks. Make sure the rotating plate and its support stand are in the correct position, remove any debris from the rotation axis or wheels, and check the counter. LG suggests pressing on one side of the microwave: if it moves unevenly, move it to a flat surface.
LG also notes that a microwave standing on "a sink or a rice bin made of metal" may make noise. For a hum that a kitchen opening onto the living room amplifies, see planning a quiet open-plan kitchen.
Why is my microwave making noise when the turntable rotates?
A turntable that grinds, rumbles, clunks or squeaks is usually out of place, dirty underneath, or overloaded. Whirlpool, Panasonic, LG and Breville all trace the noise to the glass tray, its roller ring and the floor beneath them.
Whirlpool says a thumping or rumbling sound "may occur in the microwave oven if the turntable is not installed correctly or the support roller assembly is not operating properly." It adds: "Do not operate the microwave oven without having the turntable in place."
On over-the-range models, Whirlpool's steps are to remove the turntable, clean the support and rollers, put both back, and run one cup (250 mL) of water to check.
Panasonic's manual says that when there is noise from the glass tray, "The Roller Ring and oven bottom are dirty", and that both should be cleaned "frequently to prevent excessive noise." Breville gives the same cause for its Compact Wave: a roller "not assembled properly or needs to be cleaned."
LG lists clunks from "Over size cookware", a wrongly installed rotating ring, and food on the roller and turntable. A new microwave can squeak: LG says the tape over the shaft must come off at installation. Samsung says occasional clicks from the turning glass plate are normal.
A plate that changes direction is fine too. Whirlpool calls alternating rotation "normal", set by the motor at the start of the cycle.
Why is my microwave making noise when it is off?
A microwave that is off can still run its cooling fan, start an over-the-range vent fan because of heat from the cooktop below, or hum faintly from the clock. GE and Frigidaire describe all three as normal.
The cooling fan after the door opens
GE says "It is normal for the internal fan for the electronics to continue to run for a few seconds after the microwave cycle is complete, even if the door is opened." That fan does not move air through the cavity.
Some models run longer. Whirlpool's fan noise page says that after more than 2 minutes of cooking, "the cooling fan and convection fan are ON for approximately 3 minutes or until the microwave cools down", to protect the electronics.
An over-the-range fan that starts by itself
Heat rising from the range can switch the fan on. Frigidaire's FFMV1645T manual says the vent fan "will automatically turn on at the LOW setting to cool the oven" when it gets too hot, and that "When this occurs, the vent cannot be turned off."
GE says that fan "will run up to 2 hours to keep the components cool and will then shut off on its own." Some GE models, such as the JVM3160 and JVM6172, also start the vent fan with every cooking cycle.
A faint hum or a microwave that seems to start alone
GE lists "Humming not in use" as normal: "The transformer for the clock emits a slight humming sound that is usually not noticed."
If the fan and turntable start on their own, GE's test is a cup of water or an ice cube left for 1 minute. If the water warms, the magnetron is coming on by itself, and GE says to unplug the microwave and contact service. If not, only the fan is running.
Why is my over-the-range microwave fan so loud?
An over-the-range microwave fan is loud because it doubles as a range hood. GE says it "will make a sound similar to a Vent Hood", and it may speed up on its own against a charcoal filter or restrictive ductwork.
GE explains the speed change: with the charcoal filter fitted, or where ductwork causes "an excessive back pressure on the fan", the fan "will automatically kick up to a higher speed when set on high", and stays faster on medium and low.
A rattle on top of the fan noise has other causes. Samsung says "If the filters are not installed correctly, they can cause a rattling noise", and LG says items stored on top of the unit, or an installation problem, can make it rattle.
GE also says a charcoal filter seated badly can tilt the vent cover so the light and fan come on by themselves. Its fix is to remove the vent cover, reseat the filter, and refit the cover with no gaps.
Why is my microwave sparking or crackling inside?
Sparks with a crackle or a sharp snap are arcing, which Frigidaire calls "the microwave term for sparks in the oven." The usual causes are metal in the oven, foil, food residue and running the oven empty.
Every maker we read says to stop the cycle. Frigidaire's manual: "If you see arcing, press the Cancel button and correct the problem." Breville: press STOP/CLEAR "and correct the problem or contact Breville Consumer Support for assistance."
Whirlpool says "Prolonged arcing can damage the oven", but "If caught at once, arcing should not damage the oven."
What causes arcing
Metal is the usual cause. Frigidaire lists metal or foil touching the side of the oven, foil not molded to the food, twist ties, poultry pins, gold-rimmed dishes and recycled paper towels with small metal pieces. Whirlpool adds staples, skewers and "objects with gold or silver trim or a metallic glaze".
GE adds an unused cooking probe, a metal rack left in without food on it, or a rack fitted upside down.
Arcing can start with nothing metal inside. Frigidaire's FMOS1846B manual lists "Spilled food remains in the cavity" and "The oven is operated when empty", and Panasonic warns that food residue and condensation "MAY CAUSE RUSTING OR ARCING AND DAMAGE TO THE OVEN."
Whirlpool names soil on the cavity walls and "the area where the door touches the frame", and Frigidaire's FFMV1645T manual says to keep the waveguide cover clean because "Food residue can cause arcing".
Some sparks come from the food. GE says green beans and carrots can arc, especially uncovered, seasoned with bacon grease or onions, or with little water, and that this "is not a problem with the microwave." Cover them and add water.
When arcing means the microwave is finished
A hole or peeling coating ends it. GE says that after a hole in the cavity wall "the damage is non-repairable and you should discontinue use of the product", and recommends replacing the microwave.
GE says the same for a coating that is "actively flaking" or paint "peeling anywhere inside the oven cavity". Minor chips in the coating, it says, "will not affect the product's performance."
If anything inside catches fire, Panasonic's manual says to "keep oven door closed, turn oven off, and disconnect the power cord, or shut off power at the fuse or circuit breaker panel."
Why is my microwave making noise but not heating?
A microwave that hums but does not heat may be on a weak power source, in demo mode, or have a fault. Whirlpool's first step is to heat one cup of water for 1 minute at full power and see whether it warms.
Whirlpool says an inverter or generator may power "the lights and the controls, but not the heating source", so plug it into a wall outlet. In Demo Mode, "The microwave oven light will come on, the fan will run, and the turntable will rotate", without the magnetron.
If neither applies, Whirlpool says to contact it or schedule service. Panasonic's manual says not to operate a microwave "if it is not working properly, or if it has been damaged or dropped."
Why does my microwave keep beeping?
A microwave usually beeps to confirm a key press, mark the end of a cycle, or remind you that food is still inside. GE calls the last one the Cooking Complete Reminder, a beep once a minute.
GE says the reminder "Begins 1 minute after the Cooking Complete Signal" and stops when you open the door or touch Clear/Off. Whirlpool's countertop chart uses three tones for the end of a timer and five for the end of a cycle.
Samsung says a microwave beeping when nobody is using it can be reset by switching off power at the plug or breaker for 60 seconds. "If you can hear the beeping even when the microwave does not have power, then the beeping is not coming from the microwave."
Most countertop models can be muted. GE's Sound Level pad sets the beeper from 0 (off) to 3, Samsung uses a Sound On/Off option, and Panasonic toggles Beep on or off from the Cooking Timer pad.
Over the range is harder: Whirlpool says "most audible signals can't be turned off" on its over-the-range models.
Which microwave noises mean you should stop using it?
Stop for arcing that returns once metal and food residue are gone, a popping noise that sounds electrical or mechanical, a sudden loud new noise, or a damaged door, cavity or cord. The makers send each one to service or replacement.
GE says "If the popping noise is electrical or mechanical in sound, we recommend contacting service." Samsung's test for popping is to clean the microwave and heat a bowl of water. If it still pops, request service.
The door matters most. Panasonic and Frigidaire print the same instruction: "Do not operate the oven if it is damaged", especially a bent door, broken or loose hinges and latches, or damaged door seals. Sharp says that if its drawer is damaged, do not operate it and contact a Sharp authorized servicer.
Leave the cabinet closed. Both manuals say "The oven should not be adjusted or repaired by anyone except properly qualified service personnel", and Panasonic adds that the appliance "should be serviced only by qualified service personnel."
For appliances that get louder over the years in general, see why your appliance got louder.
How loud is a normal microwave?
A normal microwave hums at about 45 to 50 dB while it heats, by LG's own description, and very few makers publish a figure for a specific model. Over-the-range vent fans are rated separately, in sones.
In our quietest microwaves guide, Breville is the only countertop maker with a model figure: 56.4 dBA for the Combi Wave while cooking, versus 59.7 dBA for the model it replaced, figures Breville takes from an independent lab. Its soft-close door was measured at 81.5 dBA against 99.6 dBA.
Frigidaire's FMOS1846B spec sheet lists "Sound Level 60 dBA" with no setting, distance or test method. LG's range and these figures were not measured the same way, so they do not rank one brand above another.
Vent fans are the loudest part of an over-the-range model. Our quietest over-the-range microwaves guide found most certified at 6 to 8 sones on high, with the quietest at 4 sones and working speeds from 1.2 sones.
Sones and decibels are different scales, as sones vs decibels explains, and the decibel chart puts 45 to 60 dBA in everyday terms.
How many microwaves have a published noise rating?
Very few microwaves have a published noise rating for cooking. Of the 13 microwaves in our catalog on October 26, 2026, 2 carry a maker's operating figure in dBA, while all 6 over-the-range models list certified vent fan ratings in sones. The counts are of our catalog, not the market.
The two are Breville's Combi Wave, with a lab figure Breville cites for microwave mode, and Frigidaire's FMOS1846B, with a bare 60 dBA on its spec sheet. One names a lab and the other names no setting at all, so the gap between them says nothing about which oven is quieter.
Breville's Compact Wave has a figure only for its soft-close door, 81.5 dBA against 99.6 for the older BMO735. The remaining ten have no operating figure, LG's two models included, even though LG's support site calls 45 to 50 dB normal for microwaves in general.
Vent fans: certified sones and marketed airflow
All 6 over-the-range models have vent fan figures certified by AHAM or HVI: 4 to 8 sones on high, and 1.2 to 2.5 sones at working speed. Each of the 6 also carries a larger airflow number in the maker's own marketing or spec sheet than the certified one. LG and Whirlpool market 400 CFM, against 230 to 290 CFM certified.
Which microwaves let you switch the beeps off?
Eight of the 13 come with a documented way to silence the beeper: both Breville models, Toshiba, Sharp's drawer, Panasonic and the three Frigidaire over-the-range models. Galanz's Retro manual has no mute procedure at all; its reminder at the close of a cycle sounds every 2 minutes until a pad is pressed or the door opens.
Whirlpool says the beeps on its over-the-range models mostly cannot be silenced. For LG's two models and the Bosch, our catalog records no verified procedure, so check the manual for your own model before buying if quiet beeps matter.
How did we put this microwave noise guide together?
Our microwave noise guide quotes the microwave support pages of GE, Whirlpool, Samsung and LG, and the use and care manuals for Panasonic's NN-SN686S, Frigidaire's FFMV1645T and FMOS1846B, Sharp's SMD2470AS microwave drawer and Breville's BMO650 Compact Wave. The rating, sone and beeper counts come from the facts recorded for the 13 microwaves in our catalog file, sorted by hand on October 26, 2026.
We did not run, record, measure, take apart or repair any microwave for this page. Each sound, cause and step is the maker's own, with its conditions. For sparks, damage and fire we repeat only the makers' instructions to stop, unplug and call qualified service, and we give no repair steps of our own.
