Why are my Mac's fans so loud?

Fans in a Mac answer to temperature sensors, not to a schedule. When the processor, the graphics or the battery warms up, macOS spins the fans faster to move more air, and slows them again once things cool down. So a loud fan is a symptom. The cause is almost always one of four things: an app keeping the chip busy, work macOS does in the background, warm or blocked air, or, rarely, a fan that is failing. This guide checks them in that order on macOS 26 Tahoe.

One family of Macs is different. The MacBook Air has had a fanless design since the M1 model in 2020 (Apple Newsroom), and Apple still describes the current one as “a silent, fanless design” (Apple). An Air that gets hot slows itself down instead of getting louder, so the first section below still applies to it.

Loud fans at a glance

Find the app that is heating your Mac

You only need Activity Monitor, which comes with macOS.

1. Open Activity Monitor. Press ⌘Space, type Activity Monitor and press Return. It also lives in Applications > Utilities.
2. Sort the CPU tab by % CPU. Click CPU at the top, then click the % CPU column heading until the highest figure is first. The column counts each core as 100%, so the scale on an eight-core Mac runs to 800% (The Eclectic Light Company). Watch for an app you are not using that stays near the top.
3. Check the GPU columns. The CPU tab also has % GPU and GPU Time columns; if you do not see them, choose View > Columns and turn them on. Games, video exports, 3D apps and browser tabs running heavy graphics can heat a Mac through the GPU while their % CPU looks modest.
4. Look at the last few minutes, not just this second. Choose Window > CPU History and Window > GPU History. Tall, packed bars while you were only reading mail mean something works in the background. Apple suggests checking GPU History when a Mac feels hot or its battery drains quickly (Apple, macOS 26).
5. Quit what you do not need. Quit the app the normal way first. If it does not respond, select it in Activity Monitor, click the Stop button (X) at the top left of the window and choose Quit. Use Force Quit only when Quit fails, because a force-quit process with open files may lose data (Apple, macOS 26).
6. Give the fans a few minutes. Fans wind down gradually as the temperature falls. If they settle after you quit an app, you found the cause; check that app for an update, a stuck sync or a misbehaving plugin.

For a column-by-column tour of the CPU and Memory tabs, see how to check CPU and memory usage on a Mac.

Fans that spin up when you are away. Activity Monitor only shows what is happening now and in the recent past, so it cannot tell you what woke the fans at 3 a.m. Orcylo groups about 700 processes under the 25 or so apps that own them and keeps 30 days of per-minute history, so you can scroll back to the minute the fans started (what Orcylo tracks).

When loud fans are just doing their job

Some work is supposed to heat a Mac. Apple names compressing HD video, playing graphics-heavy games and Spotlight indexing after you migrate data as reasons for the fans to run faster. It calls the rushing-air sound “a normal part of the cooling process” (Apple). On a developer’s Mac, add compiling a large project, building container images and running a local AI model.

Background work after a macOS update deserves a closer look, because nothing on screen explains it:

Depending on how much data you have, Apple says Spotlight indexing “can take hours or even days”. It finishes sooner when the Mac is not in use, is connected to power and is online (Apple). Quitting these processes does not help: macOS starts them again and the work picks up where it stopped.

What kernel_task at the top of the list means

kernel_task is the macOS kernel as Activity Monitor lists it. When it climbs to the top of the CPU tab on a hot Mac, it is reacting to the heat, not causing it. Apple explains that one of its jobs is to manage CPU temperature by “making the CPU less available to processes that are using it intensely”. Once the temperature drops, it reduces its activity on its own (Apple).

Thermal throttling is the visible result: the busy app runs slower so the chip stays within safe limits. You cannot quit kernel_task, and there is no reason to try. Look at the process just below it, which is usually the one producing the heat. The glossary has short entries on kernel_task and thermal throttling, and why a hot Mac feels slow covers the slowdown side.

Check the airflow and the room

A Mac can only cool itself with the air it can reach.

• Use a hard, flat surface. Apple notes that on a couch, pillow, bed or your lap, the fans “might run more” (Apple).
• Keep the vents clear. Do not cover a laptop’s ventilation openings or push anything into them, and do not put anything over the keyboard (Apple).
• Mind the room. Apple asks for an ambient temperature between 10 and 35 °C (50 to 95 °F) for Mac laptops. When the room is warm, the fans turn on sooner and run faster.
• Consider dust on an older Mac. Dust and pet hair that collect on the vents over the years block the same airflow. If an older Mac is louder than it used to be under the same work, have an Apple Store or Apple Authorized Service Provider look at it rather than opening it yourself.

Turn on Low Power Mode to cap fan noise

Low Power Mode is the macOS setting that trades some speed for lower energy use. Since macOS Sequoia 15.1 it also “helps reduce fan noise for tasks done in quieter environments” on the Macs Apple lists for it (Apple). On macOS 26:

• Mac laptop. Choose Apple menu > System Settings > Battery. Set Low Power Mode, or, if your Mac shows an Energy Mode menu instead, choose Low Power for “On battery”, “On power adapter” or both (Apple, macOS 26).
• Mac desktop. Choose Apple menu > System Settings > Energy and turn on Low Power Mode, which Apple describes as reducing fan noise for “environments and tasks that require minimal noise” (Apple, macOS 26).
• Shortcut. Energy modes can also be switched from Control Center.

Apple’s list of models where Low Power Mode reduces fan noise, as published on 21 September 2026:

The table works the other way round too. High Power Mode “allows the fans to run at higher speeds”, and Apple warns you may hear additional fan noise when it is on. If your MacBook Pro, Mac mini or Mac Studio is louder than you expect, check that it is not set to High Power.

Read temperatures and fan speed

Neither Activity Monitor nor System Settings shows degrees or fan RPM. Many guides suggest this command:

sudo powermetrics --samplers smc

On Apple silicon it no longer works. We tested it on an M4 Mac mini on 1 October 2026, and powermetrics answered powermetrics: unrecognized sampler: smc; its help screen lists no SMC sampler at all. Two built-in commands still tell you something:

pmset -g therm

This needs no admin password. It prints any thermal or performance warning macOS has recorded, and “No thermal warning level has been recorded” means the Mac has not had to slow down for heat.

sudo powermetrics --samplers thermal -n 1

The thermal sampler reports macOS’s thermal pressure level, which sits at Nominal on a Mac that is coping and rises as it heats up. Neither command gives you a temperature or a fan speed.

For actual degrees and RPM you need an app that reads the Mac’s sensors. Orcylo shows 38 temperature sensors grouped by component and the current fan speed in its Thermals view and menu bar item (see Orcylo’s features). It reads the fans but does not control them; macOS keeps deciding their speed. Two caveats from Apple apply to every app of this kind. The sensors measure internal components, and the case is much cooler. And Apple says never to use third-party apps to diagnose possible hardware issues (Apple). Other monitors that show sensors are compared in the best system monitors for Mac.

When the noise points to a hardware problem

Treat a loud fan as a possible hardware fault in three situations:

• Loud but idle. The fans run fast while Activity Monitor shows little activity, the vents are clear and the room is cool.
• The wrong sound. You hear grinding, clicking or rattling rather than the rush of moving air.
• Loud from the start. The fans roar from the moment the Mac starts, before any app has opened.

Work through these steps:

1. Restart first. For fans that run fast without heavy use, Apple’s first step on a Mac with Apple silicon is to close and open the lid of a laptop, or restart. On an Intel-based Mac, reset the SMC instead (Apple).
2. Run Apple Diagnostics. Shut down and disconnect accessories except keyboard, mouse, display and power. On Apple silicon, press and hold the power button until Options appears, release it, then press and hold ⌘D until the Mac restarts. On an Intel Mac, hold D as it starts up. In macOS Tahoe 26 and later you pick which diagnostic to run (Apple).
3. Read the reference code. Apple Diagnostics reports PPF001, PPF003 or PPF004 when “there may be an issue with the fan”. For those codes, Apple’s advice is to contact Apple or visit an Apple Store or Apple Authorized Service Provider (Apple).

If the diagnostics come back clean and the noise is rushing air, the fan is fine. The answer is back in the first section: something on the Mac is working harder than you think.