Open Activity Monitor to see what's using your memory right now

Activity Monitor is the built-in Mac tool that shows you exactly which programs are consuming memory and how much. It takes 30 seconds to open and read. Press Command + Space to open Spotlight search, type "Activity Monitor", and press Enter. The window that opens shows every running program and how much memory each one is using.

When Activity Monitor opens, you're looking at the Processes tab by default. Look for the column labeled "Memory" — this shows megabytes (MB) or gigabytes (GB) for each program. The programs using the most memory appear at the top if you click the Memory column header once. If a program is using 500 MB or more on a Mac with 8 GB of total memory, that's worth noticing. On a Mac with 16 GB, the same program might be normal.

The number you care about most is in the bottom right corner: "Memory Pressure". This is a colored dot that tells you whether your Mac has enough free memory right now. Green means you're fine. Yellow means your Mac is using most of its memory but still has room. Red means your Mac is out of memory and will start using your hard drive as temporary memory, which makes everything slow.

Key Takeaways

  • Activity Monitor shows you every running program and how much memory it's using — open it with Command + Space, then type "Activity Monitor".
  • The Memory Pressure dot in the bottom right tells you whether your Mac has free memory (green), is running low (yellow), or is out of memory (red).
  • Programs using 500 MB to 1 GB are normal; anything consistently above 2 GB for a single program is worth investigating.
  • Restarting your Mac clears memory and closes programs you're not actively using, which often fixes slowness caused by memory pressure.
  • Safari, Chrome, and Slack often use the most memory because they run many background processes — closing unused tabs and windows helps.

Understand what the numbers mean for your specific Mac

The amount of memory your Mac has determines what "high" usage looks like. You can find your total memory by clicking the Apple menu in the top left, selecting "About This Mac", and looking at the line that says "Memory". Most newer Macs have 8 GB, 16 GB, or 24 GB.

If your Mac has 8 GB total and Activity Monitor shows 7 GB in use, your Mac is under stress and will feel slow. If your Mac has 16 GB and shows 7 GB in use, you still have plenty of room. The Memory Pressure indicator accounts for this automatically — that's why the colored dot is more useful than the raw number.

One program using 2 GB is not necessarily a problem. One program using 6 GB on an 8 GB Mac is a problem. The question is always: how much memory is left over for everything else you want to do?

Find which programs are using the most memory

Click the Memory column header in Activity Monitor to sort programs by memory use, highest first. The top five programs on your list are the ones affecting your Mac's speed the most. Write down the names of any program using more than 1 GB consistently.

Some programs are memory hogs by design. Google Chrome uses more memory than Safari because it runs each tab in its own process for safety. Slack uses memory because it's constantly checking for new messages. Adobe Creative Suite programs (Photoshop, Premiere, After Effects) use large amounts because they work with big files. These are not broken — they're just heavy programs.

If you see a program you don't recognize using a lot of memory, search for its name online to understand what it does. Sometimes background programs installed with other software use memory without you knowing they're running. If you don't need it, you can quit it by selecting it in Activity Monitor and clicking the X button at the top left.

Check memory usage over time with the System Memory tab

Activity Monitor has a second way to look at memory: the System Memory tab at the bottom of the window. Click it to see a graph of your memory use over the last few minutes. This shows you whether memory pressure is constant or happens only when you do certain things (like opening many browser tabs or running video editing software).

The graph breaks memory into colored sections: yellow is memory in active use, orange is memory used by the system, and blue is memory available for new programs. If the graph is mostly yellow and orange with very little blue, your Mac is running low. If you see the blue section shrink when you open a specific program, that program is the one causing the pressure.

Watch this graph while you do the things that make your Mac feel slow. If memory pressure jumps to red when you open a certain program or website, you've found the culprit. This is more useful than looking at a single snapshot, because memory use changes constantly.

Restart your Mac to free up memory quickly

Restarting closes every program and clears all memory. After restart, your Mac starts fresh with most of its memory available. If your Mac feels slow and Memory Pressure is yellow or red, restart it. This is the fastest way to get back to normal speed.

You don't need to restart every day. If Memory Pressure is green and your Mac feels fast, leave it running. But if you notice Memory Pressure creeping into yellow or red, or if your Mac has been on for more than a week, restart it. A restart takes 2 to 5 minutes and usually fixes slowness caused by memory pressure.

To restart, click the Apple menu, select "Restart", and click "Restart" again. Save any open work first — restarting closes all programs without asking.

Close programs and browser tabs to lower memory pressure

If you don't want to restart, you can free up memory by closing programs you're not using. Look at Activity Monitor, find programs using 500 MB or more that you're not actively working in, and quit them. Click the program name, then click the X button at the top left of the Activity Monitor window.

Browser tabs are a common memory drain. Each open tab in Chrome uses 50 to 150 MB. If you have 30 tabs open, that's 1.5 to 4.5 GB just for tabs. Close tabs you're not reading. If you need to keep many tabs, use Safari instead of Chrome — Safari uses less memory per tab.

Closing one program might not change Memory Pressure much. Closing five programs might. The goal is to get Memory Pressure back to green. Once it's green, your Mac will feel noticeably faster.

Know when memory problems point to a bigger issue

If Memory Pressure is constantly red even after you close programs and restart, your Mac might not have enough memory for how you use it. This is especially true if you run memory-heavy software like video editing, 3D rendering, or data analysis. In that case, you have two options: upgrade your Mac's memory (if it's upgradeable) or use fewer programs at once.

If a single program consistently uses 80% of your Mac's total memory and you're not doing anything unusual in that program, the program might have a memory leak — a bug that causes it to use more and more memory over time. Try updating the program to the latest version. If the problem continues, contact the software maker's support.

If Memory Pressure is red and Activity Monitor shows no single program using excessive memory, your Mac's storage drive might be full. A full drive forces your Mac to use memory as temporary storage, which is much slower. Check your storage by clicking the Apple menu, selecting "About This Mac", and clicking "Storage". If the bar is mostly full, you need to delete files or move them to external storage.

Frequently Asked Questions

What does "Memory Pressure" mean?

Memory Pressure is a measure of how much of your Mac's total memory is in use right now. Green means you have plenty of free memory. Yellow means you're using most of it but still have room. Red means your Mac has run out of memory and is using your hard drive as temporary memory, which makes everything slow.

Is it bad to have one program using 2 GB of memory?

It depends on your Mac's total memory. On an 8 GB Mac, 2 GB is 25% of your total, which is fine. On a 16 GB Mac, it's only 12.5%, which is very fine. The question is whether you have enough memory left for everything else. If Memory Pressure is green, you're okay.

Why does Chrome use so much more memory than Safari?

Chrome runs each tab and extension in its own separate process for security — if one tab crashes, the others keep working. This design uses more memory. Safari runs tabs more efficiently. If memory is tight on your Mac, Safari will feel faster.

Do I need to close programs to save memory, or can I just minimize them?

Minimizing a program doesn't free memory — the program is still running and still using memory. You have to quit the program (close it completely) to free that memory. In Activity Monitor, select the program and click the X button.

What's the difference between MB and GB in the Memory column?

MB (megabytes) and GB (gigabytes) are just different units. 1 GB equals 1,000 MB. Activity Monitor shows larger numbers in GB and smaller ones in MB. A program using 500 MB is the same as 0.5 GB.