Where to find memory pressure
Open Activity Monitor and click the Memory tab. The graph at the bottom is Memory Pressure. Next to it you'll see Physical Memory, Memory Used, Cached Files, Swap Used and a breakdown into App Memory, Wired Memory and Compressed.
Why "Memory Used" being high is fine
macOS deliberately uses spare memory to keep recently used files and apps ready (that's Cached Files). Unused memory is wasted memory. That's why the pressure graph matters more than how much memory is "used".
What the colours mean
| Graph colour | What's happening | What to do |
|---|---|---|
| Green | Everything fits comfortably | Nothing |
| Yellow | macOS is compressing memory to make room | Fine now and then; if it's often yellow, close what you don't need |
| Red | Memory is full and macOS is swapping to disk | Quit apps or tabs; your Mac will feel slow until you do |
How to lower memory pressure
- Sort by Memory. In the Memory tab, click the Memory column to see which apps use the most.
- Close heavy tabs and windows. Browsers are usually the biggest users. Each tab can hold hundreds of megabytes.
- Quit apps you're not using. Especially design tools, virtual machines, containers and IDEs.
- Restart long-running apps. Some apps grow over days of use. Quitting and reopening frees that memory.
- Trim login items. System Settings › General › Login Items lists apps that open at startup and keep running.
- Restart your Mac if pressure stays high with little open.
You don't need "memory cleaner" apps. macOS manages memory well on its own; closing what you don't need is the fix.
What swap means
Swap Used is memory macOS has moved to your disk because RAM ran out. A little swap is normal. Swap that keeps growing while the graph is red is the clearest sign you need to close things, or that your workload needs a Mac with more memory.