Tidy MacHow much memory is my Mac really using?
Memory used on a Mac is app memory + wired + compressed. Cached files look “used” but are freed the moment an app needs them. Paste vm_stat below to see your numbers in GB.
vm_stat| App memory | 5.4 GB | Used by apps right now |
| Wired | 2.32 GB | Kept by macOS, can’t be compressed |
| Compressed | 1.5 GB | Idle memory squeezed to save room |
| Cached files | 3.67 GB | Reusable, freed instantly when needed |
| Free | 0.18 GB | Not used at all |
Short on disk space as well?
Tidy Mac leaves memory to macOS, which manages it well. It finds the disk space your Mac is hiding, System Data included; a nearly full disk is what makes swap hurt. $9.99 once, 2 Macs.
How it works
vm_stat counts memory in pages. The checker multiplies each count by the page size in the first line (16 KB on Apple silicon, 4 KB on Intel) and groups them like Activity Monitor:
- App memory ≈ anonymous pages − purgeable pages.
- Cached files ≈ file-backed pages + purgeable pages.
- Memory used = app memory + wired + compressed.
Activity Monitor’s figures can differ slightly; these are close approximations from the same counters. Running out of disk space can also cause swap trouble: see what /private/var/vm is.
Questions
How do I check memory usage on a Mac?
Open Activity Monitor › Memory for the graph and Memory Pressure. In Terminal, vm_stat prints the raw page counts; paste them here to get the same groups in GB.
Is it bad that my Mac uses almost all its RAM?
No. macOS keeps recently used files in memory (Cached Files) and compresses idle memory instead of leaving RAM empty. What matters is memory pressure and swap: if pressure is green and swap stays low, you have enough.
What is compressed memory?
Memory that macOS squeezed to make room, which is faster than writing it to disk as swap. Some compression is normal; lots of it plus growing swap means you’re short on RAM.
Can a cleaner “free up RAM”?
Not usefully. macOS manages memory itself, and forcing caches out just makes apps reload them. Quit apps you don’t need instead.