Guides/How to free up RAM on a Mac

How to free up RAM on a Mac, and when you don’t need to

Atta 🐬

Founder, Vitals

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Quick answer

To free up RAM on a Mac, open Activity Monitor, click Memory and sort by the Memory column, then quit or reopen the app at the top. Browsers, chat and code editors, virtual machines, Docker and local AI models hold the most. First check Memory Pressure at the bottom of the tab: if it is green, there is nothing to free, because macOS uses spare memory for files it hands back the moment an app needs it. Memory cleaner apps and `sudo purge` do not help. Vitals, a system monitor for the Mac, shows each app’s memory with its helpers counted in, and tells you when an app keeps growing.

How to free up memory on a Mac

  1. 01 Open Activity Monitor (press ⌘Space and type its name) and click Memory.
  2. 02 Look at Memory Pressure at the bottom. If the graph is green, stop here: the Mac has enough memory, however full Memory Used looks.
  3. 03 Click the Memory column header to sort by it, and choose View → All Processes, Hierarchically so each app’s helper processes sit under it.
  4. 04 Quit the apps near the top that you are not using. If one you are using has grown far beyond its usual size, save your work, quit it and open it again.
  5. 05 In a browser, close or reload the heaviest tabs instead of quitting the whole browser. Its own task manager shows which they are.
  6. 06 Wait a minute and look at Memory Pressure again. It should be back to green, and Swap Used should stop growing.

If memory pressure stays red after you have quit the apps that were using the memory, restart the Mac. Memory held by a stuck system process is freed no other way.

Most advice about freeing RAM starts from the wrong number. Memory Used near the total is how macOS is meant to work: memory nobody is using is kept busy holding recently used files, and handed back the moment an app asks for it. What matters is whether apps get the memory they ask for, which is what Memory Pressure shows. When it turns yellow or red, one or two apps are usually holding most of it, and the table below says how to free each.

What holds the memory, and how to free it

What is using itHow to free itWhere to look
A browser with many tabs Close or reload the heaviest tabs, and turn on Memory Saver in Chrome The browser’s task manager
Slack, Teams, Discord, VS Code and other apps built on web technology Quit them when you are not using them, or reopen them once a day Activity Monitor → Memory, with View → All Processes, Hierarchically
A virtual machine in Parallels, VMware Fusion or UTM Shut down VMs you are not using, or give them less memory in their settings Activity Monitor → Memory
Docker Lower Memory limit in Docker Desktop, or turn on Resource Saver docker stats
A local AI model Unload the model or quit the app that runs it Activity Monitor → Memory
An app that keeps growing Quit and reopen it, and update it Its Memory figure over an hour or two

When you do not need to free RAM

Unused memory is wasted memory. macOS keeps recently used files in RAM as Cached Files, so opening them again is instant, and it compresses memory an app is not using before it moves anything to disk. Both show as memory in use, and both give way when an app needs the room.

So a Mac with 15 GB of 16 GB in use and green Memory Pressure is healthy, and freeing memory would only make it slower while macOS reads those files back in. Free memory when pressure is yellow or red while you work, or when the Mac slows down and Swap Used keeps climbing.

What actually frees memory

Memory belongs to the app that asked for it, so the way to free it is through that app.

  • Quit apps you are not using. On a Mac, closing an app’s last window often leaves the app running; press ⌘Q to quit it.
  • Close browser tabs you do not need, especially web apps and video. See Chrome using too much memory for how to find the heavy ones.
  • Stop apps you never use from opening at login, in System Settings → General → Login Items & Extensions.
  • Give virtual machines and Docker a smaller share of memory. Each holds what you give it while it runs.
  • Restart an app that leaks: its memory keeps growing while you use it no more than usual. Updating it often fixes the leak.

What does not work: memory cleaners and purge

Memory cleaner apps and the sudo purge command empty the file cache and push apps’ memory out to disk. The number drops for a moment, then macOS reads the same files and pages back in, and the Mac is slower until it has. Nothing that was using memory has stopped.

Quitting system processes in Activity Monitor does not help either. macOS starts them again, and many of them, such as WindowServer and kernel_task, are only large because of what your apps ask them to do.

When the Mac really needs more memory

If Memory Pressure turns yellow during the work you do every day, with only the apps you need open, the Mac is short of memory for that work. Swap on an Apple silicon Mac’s SSD is fast, so yellow is workable; red, or a Mac that stalls when you switch apps, is not.

Unified memory in an Apple silicon Mac is part of the chip and cannot be added later. Until the next Mac, the choices are fewer apps open at once, lighter alternatives to the heaviest ones, and smaller allocations for virtual machines, Docker and AI models. When you buy, use Memory Pressure on this Mac as the guide to how much you need.

What Vitals adds

Vitals shows each app’s memory with its helpers counted in, and tells you when one keeps growing.

  • One row per app with its helper processes counted in, so a browser or Slack is one figure: close to what you get back by quitting it
  • Click a browser to see its memory split into tabs, extensions, graphics and the browser itself, and open the Containers tab for each Docker container’s memory
  • 30 days of memory for every app, so you can tell an app that has always been large from one that is growing
  • A notification when an app keeps using more and more memory, and when the Mac runs short of memory, naming the two apps using the most
  • Memory pressure in the menu bar, in place of memory used, if you like

Good to know

  • Vitals does not free memory or purge caches. It shows which app to quit, and quits it after asking.
Get Vitals for $9 $9 during the launch, $29 after it. 14-day refund.

Questions people ask

How do I clear RAM on my Mac?

Quit the apps you are not using, starting with the ones at the top of Activity Monitor’s Memory tab, and close heavy browser tabs. If memory pressure stays red after that, restart the Mac.

Is it bad that my Mac is using all its memory?

No, if Memory Pressure is green. macOS fills spare memory with cached files and gives it back as soon as an app needs it. It matters only when pressure is yellow or red.

Does sudo purge free RAM on a Mac?

It empties the file cache, so Memory Used drops for a moment. macOS then reads those files back in, so the Mac is slower for a while and no app has more memory than before.

Do RAM cleaner apps work on a Mac?

No. They push out memory that apps and macOS ask for again straight away. The figure looks better for a minute; the Mac does not run faster.

How much RAM do I need on a Mac?

Enough to keep Memory Pressure green in your normal work. For most people that is 16 GB; developers running containers or virtual machines, and people running local AI models, often want 32 GB or more.

Is there an app that shows which app is using my Mac’s memory?

Vitals shows each app’s memory with its helper processes counted in, keeps 30 days of it, and sends a notification when an app keeps growing or the Mac runs short of memory.

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