Activity Monitor for Mac: What It Is, How to Use It, & Why

Activity Monitor is a powerful built-in tool for MacOS that is commonly used by advanced users, but is often overlooked or unacknowledged by more casual Mac fans. Typically when Activity Monitor is accessed, it’s because something is going wrong, and the user is attempting to discover which process(es) are errant with resource usage. If you have ever been in a situation wondering what is making your Mac run slow, run hot, run fans on high, which app is frozen, what apps are eating up your memory, what app or process is consuming your battery and energy, or engaging in tons of disk reads and writes, Activity Monitor is where you can discover all of this information and more, plus take direct action to terminate processes and apps.

What is Activity Monitor?

Activity Monitor is a system resource monitor for MacOS that is found within the /Applications/Utilities/ folder. When opened, you can use Activity Monitor to get a detailed look about the following types of system activity:

• CPU usage – see what processes and apps are using processor, and the % they are using
• Memory usage – see what apps and processes are using memory, and how much they are using
• Energy usage – useful to determine what apps are using energy, particularly helpful for MacBook laptops
• Disk activity – monitor apps and processes disk reading and disk writing activity
• Network usage – see what apps and processes are transferring data over the internet or network, both sending and receiving

Activity Monitor for Mac is kind of like the equivalent of Task Manager from Windows, combined with a series of system performance and resource monitoring dashboard features. If you’re coming from the PC world that might be helpful to remember. And while you can force quit apps with a keyboard shortcut, you can also do that from Activity Monitor too.

How to Open Activity Monitor on Mac

There are a few ways to open Activity Monitor on MacOS.

• Hit Command+Spacebar and type “Activity Monitor” and hit the Return key (this opens Activity Monitor via Spotlight)

You can also open Activity Monitor by going to Applications > Utilities, and doubleclicking on Activity Monitor.

With Activity Monitor open, you’ll now have access to the full feature suite of tools to monitor system activity, including CPU, memory, energy, disk, and network.

How to Use Activity Monitor on Mac

Once you’re in Activity Monitor, you can use it to track down various things.

Before doing anything else, go to the “View” menu and choose “All Processes” to get the more amount of information about your Mac and the running apps and processes behind the scenes.

1: Find an app/process slowing things down, frozen app, or app using a lot of CPU

Go to the CPU tab, then sort by the “% CPU”

1b: Force quit an app or process from Activity Monitor

If you see an app/process that you want to force quit, for example if you see an app in red and says (Not Responding) next to it, you can force quit that app by selecting it, then clicking on the (X) button in the toolbar of Activity Monitor to force quit.

2: Check memory usage of apps and processes, and check memory pressure

Go to the “Memory” tab and sort by “Memory” to see the apps/processes using the most memory.

Additionally, pay attention to Memory Pressure, at the bottom of the Memory screen. If the graph is all green the Mac has plenty of memory, if the graph is yellow it’s starting to use a lot of swap and virtual memory, and if the graph is in the red, you’re running out of memory and should quit some apps or processes to free up resources.

3: Find what apps are draining your battery life

If you have a MacBook laptop, the “Energy” tab is particularly useful to determine which apps or processes are draining the battery life of your MacBook Air or MacBook Pro.

Go to the “Energy” tab and then sort by Energy Impact to see the top energy users (there is usually correlation between these and CPU use and/or disk use).

4: Check disk activity

If your Mac feels weirdly slow, another thing to check is disk read/write activity. Go to the “Disk” tab and sort by disk writing and disk reading, and look for anything unusual.

This is particularly useful for older traditional platter hard drives. But excessive disk read/write is also useful for SSD users because too much read/write can wear out the lifespan of an SSD.

5: Monitor network activity

If you’re curious which apps or processes are sending and receiving data, the “Network” tab is quite useful for this purpose. You can see how much data individual processes are transmitting too.

Why use Activity Monitor on Mac?

The most common reasons Mac users end up using Activity Monitor are related to troubleshooting. perhaps you’re figuring out what is causing a performance issue, or a slow or sluggish Mac, or maybe an app is unresponsive or frozen and you need to force quit the app, or maybe you’re trying to figure out what apps are eating all of your battery life, or what apps are consuming your internet bandwidth.

Activity Monitor can be super useful for all of this and more, it offers a very easy way to monitor system activity and system health, and to help optimize Mac performance.

Familiarize yourself with Activity Monitor, it’s a fantastic tool

Activity Monitor should be a known tool and resource for all Mac users, not just advanced power users. Whether you want to quit a frozen or misbehaving app, check general system load, determine what is causing performance issues, or similar, it’s an essential tool for the MacOS toolbox.