Mac overheating? Every cause and what to do

What makes a Mac overheat?

Each cause has a sign you can check, and a guide that goes deeper.

Is an app making your Mac hot?

A busy processor makes heat. An export, a render, a game or Spotlight indexing after you move your data to a new Mac can keep it busy for minutes.

1. Open Activity Monitor. It’s in Applications > Utilities, or search for it with Spotlight.
2. Click CPU, then click the % CPU column heading to sort the list, busiest first.
3. Watch the top of the list for a minute. An app that stays there is making the heat.
4. If you don’t need that app now, quit it, saving your work first. If it’s doing work you asked for, let it finish on a desk with room for air.

Activity Monitor counts each processor core as 100%, so a render on many cores shows far more than 100%. Why is my MacBook getting hot? covers busy apps and heat in more detail.

Is your Mac getting enough air?

The fans can only cool your Mac if air can reach it. Apple’s advice for Mac laptops:

• Use a hard, flat surface, such as a table or desk. On a couch, a pillow, a bed or your lap, the fans may run more.
• Keep the vents clear. Keep things off the keyboard and out of the vent openings.
• Keep the room in range. Use your Mac laptop where it’s between 10 °C and 35 °C (50 °F and 95 °F). Don’t leave it in a parked car, which can get hotter than that.
• Install software updates, and use only Apple-authorized power adapters.

Why is my Mac’s fan so loud?

The fans speed up to move more air when your Mac works hard. Apple calls the rushing-air sound a normal part of cooling, and says that in a warm room the fans turn on sooner and run faster.

If the fan stays loud for minutes, something is usually keeping the processor busy, so check Activity Monitor’s CPU list as above. MacBook fan loud? What’s making it spin up covers what to do, and what to try when the fan stays loud with nothing busy.

Why is kernel_task using so much CPU?

kernel_task is part of macOS, not an app you opened. Apple says one of its jobs is to help manage the processor’s temperature, by making the processor less available to processes using it heavily. It responds to heat; it doesn’t cause it. When the processor cools, kernel_task reduces its activity on its own.

In the picture above, kernel_task is at 88.7% while Blender renders. Don’t try to quit kernel_task: look past it for the app doing the work. kernel_task high CPU? Your Mac is cooling itself explains it in full.

Is my Mac throttling?

Throttling is macOS slowing the processor so it can cool. macOS tracks a heat level in four steps, which Apple’s developer documentation calls thermal states:

At serious and critical, macOS reduces performance, so heavy work takes longer until your Mac cools. Mac thermal throttling: what the heat level means shows how to check for it.

Why does my MacBook get hot while charging?

Many people plug in for big jobs, such as exports and renders, so a busy processor adds its heat while the battery charges. Apple says a MacBook Pro and its power adapter may become very warm during normal use, and asks you to leave air around both.

If the battery gets too warm, charging may stop at 80%. Move your Mac somewhere cool and well ventilated, with the power adapter in the open too. MacBook hot while charging: normal or not? explains the 80% stop and when heat while charging is a problem.

How can I check my Mac’s temperature?

macOS doesn’t show your Mac’s chip temperature in degrees. Apps from other developers read sensors inside the Mac, but Apple says those readings aren’t the temperature of the case, which is much cooler, and that you should never use such apps to diagnose hardware problems.

What macOS does report is its heat level. In Terminal, pmset -g therm shows thermal conditions that affect CPU speed. For the room, Apple gives a range for Mac laptops, 10 °C to 35 °C, rather than a chip temperature. How to check your Mac’s CPU temperature walks through both Terminal checks and what their results mean.

When should I contact Apple?

If your Mac stays hot, or its fans run fast while it isn’t doing heavy work and has room for air, follow Apple’s steps:

1. Check Activity Monitor’s CPU list for a process putting a heavy load on the processor.
2. Close the lid and open it again, or restart your Mac.
3. On an Intel-based Mac, reset the SMC (System Management Controller), the chip that manages power and fans. On a Mac with Apple silicon, restarting does that.
4. If the problem continues, contact Apple, visit an Apple Store or go to an Apple Authorized Service Provider.

Questions people also ask

How hot is too hot for a Mac?

Apple gives a room temperature range, not a chip limit: use a Mac laptop where it’s between 10 °C and 35 °C (50 °F and 95 °F). If your Mac stays hot during light work, follow Apple’s steps above.

Why is my Mac hot when I’m not doing anything?

Something may be working in the background, such as Spotlight indexing, a sync or an app that opens at login. Sort Activity Monitor’s CPU list by % CPU to see what it is.

Can heat damage my MacBook’s battery?

Yes. Apple says ambient temperatures above 35 °C (95 °F) can permanently damage battery capacity, so the battery won’t last as long on a charge, and that charging in that heat can damage it further. Even storing a battery somewhere hot can harm it.