How to use Activity Monitor on a Mac (macOS 26)

You are viewing the macOS 26 version of this guide, recorded on macOS Tahoe 26 (MacBook Pro) on 4 October 2026. It is kept as it was and not updated. See the macOS 27 version.

howtosimply.com/guides/how-to-use-activity-monitor-on-a-mac/ · Checked 4 October 2026 · MacBook Pro · macOS Tahoe 26

In this guide

Open Activity Monitor
Look at the CPU tab
Look at the Memory tab
Look at the Energy tab
Look at Disk and Network
Find a process
Quit a hung app
Good to know
Sources

Quick answer

Open Activity Monitor from Applications, Utilities, or search for it with Spotlight. The tabs CPU, Memory, Energy, Disk and Network show what each app is using right now. Click a column heading to sort, and select an app and click the stop button to quit one that has hung.

4 of 7 steps with real screenshots · 3 official sources below

Device: Mac
Shown on: macOS Tahoe 26 (MacBook Pro)
App: Activity Monitor
Real screenshots: 4 of 7 steps
Checked: 4 October 2026
Sources: 3 official, linked below

Step by step

Open Activity Monitor
Press Command + Space, type Activity Monitor and press Return. The app is in Applications, Utilities.
Done
Tap the picture to see it full size
Look at the CPU tab
Click the % CPU column to put the busiest process at the top. An app that stays high when you are not using it may be stuck. The value can go above 100 percent, because each processor core counts as 100.
Done
Tap the picture to see it full size
Look at the Memory tab
The Memory Pressure graph at the bottom matters more than the numbers. Green is fine. Yellow or red means the Mac is short of memory and is slowing down: close apps and browser tabs.
Done
Tap the picture to see it full size
Look at the Energy tab
On a MacBook, Energy Impact and the 12 hr Power column show which apps have used the most battery.
Done
Look at Disk and Network
They show how much each process reads, writes, sends and receives. This is where you see what is busy when the Mac seems to work by itself.
Done
Find a process
Type a name in the search field at the top right. The View menu switches between All Processes, My Processes, Windowed Processes and other groups.
Done
Tap the picture to see it full size
Quit a hung app
Select the process and click the stop button, the X in a circle, in the toolbar. Choose Quit first. Use Force Quit only if that does not work, because unsaved changes are lost.
Done

What we saw on our device

Open Activity Monitor: On our MacBook Neo it opened on My Processes, shown under the window title.
Look at the CPU tab: On our MacBook Neo, with the list sorted by % CPU, kernel_task was at the top.
Look at the Memory tab: On our MacBook Neo, with 8 GB, the graph was yellow, with 6,97 GB Memory Used and 2,75 GB Swap Used.
Look at Disk and Network: On our MacBook Neo the Disk tab lists Bytes Written and Bytes Read per process, with Data read and Data written totals at the bottom.
Quit a hung app: On our MacBook Neo, with Calculator selected, the stop button asked: Do you really want to quit "Calculator"?

About this guide

Activity Monitor is the Mac's counterpart to the Windows Task Manager. It answers the questions behind most performance complaints: which app is keeping the processor busy, which one is eating memory, and what is draining the battery.

Menu names are from recent versions of macOS, where the settings app is called System Settings.

Some pictures are simplified diagrams of the screen, not screenshots.

Good to know

Leave alone anything you do not recognise that belongs to the user root or to the system, such as kernel_task or WindowServer. They are parts of macOS.

Double-click a process to see details about it.

A quicker way to end one frozen app: how to force quit a frozen app on a Mac.

What to do with what you find: Mac running slow: 8 fixes to try and MacBook getting hot: 7 things to check.

In short: Open Activity Monitor, sort by % CPU, check Memory Pressure, Energy on a MacBook, search for a process, stop button to quit a hung app.

Sources