Warm is normal; hot is worth a look
Every Mac makes heat when it works. A MacBook that feels warm on the bottom while you edit photos, join a video call or play a game is doing what it was built to do. Inside, sensors watch the temperature constantly, and on Macs with fans, the fans speed up by themselves to carry the heat away.
Apple's guidance is to use a Mac laptop where the room is between 10° and 35° C (50° and 95° F). That's the air around the Mac, not the case. Leave it out of parked cars, which get far hotter than that.
What deserves a closer look is heat that doesn't match what you're doing: a Mac that's hot while you're only reading email, warm with nothing open, or hot enough to be uncomfortable on your lap.
Find what's making the heat
macOS has a built-in tool for this: Activity Monitor.
- Open it with Spotlight: press Command-Space, type Activity Monitor and press Return. (It also lives in Applications › Utilities.)
- Click CPU at the top of the window.
- Click the % CPU column header so the busiest processes are at the top.
- Look for anything high that you aren't using right now. An app sitting at 100% or more, for minutes, while you're not using it, is a likely heater.
- The Energy tab ranks apps by Energy Impact, which is often easier to read.
To stop something, select it and click the Stop button (the ⓧ in the toolbar), then choose Quit. Use Force Quit only if an app is frozen and won't respond, because it can lose unsaved work.
If you see kernel_task near the top
kernel_task is part of macOS, and Apple explains that one of its jobs is to manage CPU temperature. When the chip runs too hot, kernel_task takes CPU time away from other processes so they make less heat. It isn't the cause; it's macOS reacting to heat that's already there. Look further down the list for what's really working hard, and kernel_task settles by itself once things cool.
The usual causes
- Browsers with many tabs. Each tab can run its own scripts and video. A few busy tabs, especially with video, can keep the chip working. Close what you don't need, and check whether one site is the culprit by watching Activity Monitor as you close tabs.
- Video calls. Your camera, the video you send and the video you receive are all processed live. Calls with many participants, virtual backgrounds or screen sharing add more.
- Background catch-up. After an update, or when you add lots of photos, macOS rebuilds its search index and analyzes your library. That can mean hours of steady work. Our guide to a Mac that's hot after an update covers it.
- Sync and backups. Cloud storage and backup apps can work hard after many files change.
- Heavy work. Exporting video, compiling code, rendering, games: heat is expected, and it ends when the work does.
How to cool it down
- Give it a hard, flat surface. Apple says not to use a Mac laptop on a bed, a pillow or under bedding, and to use a stable surface that allows good ventilation. Don't cover the keyboard or put anything into vents.
- Mind the room. A sunny desk or a hot room makes everything harder.
- Quit what you don't need, starting with whatever Activity Monitor ranks highest.
- Turn on Low Power Mode on supported Macs: System Settings › Battery, then choose Low Power Mode under Energy Mode, for On battery, On power adapter, or both. It reduces energy use, and on macOS Sequoia 15.1 and later, Apple says it also helps reduce fan noise on Macs with fans.
- Restart if a process seems stuck. Apple also suggests closing and opening the lid. On an Intel-based Mac, Apple lists resetting the SMC as a further step.
- Keep macOS and your apps up to date, so you have the latest fixes.
When to contact Apple
Get help from Apple if your Mac is hot with nothing running for days, its fans run at full speed while it's idle, or you see a warning about temperature. Stop using it and contact Apple straight away if the case no longer sits flat, the trackpad stops clicking properly, or the battery looks swollen.
A note on temperature apps: Apple points out that third-party apps that show temperatures read sensors inside the Mac, not the outside of the case, which is much cooler. They're useful for seeing trends, but Apple says never to use them to diagnose a hardware problem. If you suspect one, ask Apple.