What macOS shows on its own
Finder shows free space in a window’s status bar (View, Show Status Bar), and System Settings, General, Storage has the breakdown.
How Multimeter shows it
- Purgeable space counts as free, the way Finder counts it. The menu shows how much is available, like “120 GB available”.
- Checked once a minute; disk space doesn’t change fast.
- Alerts default to a warning above 85% full and critical above 95%.
- For an external drive that isn’t plugged in, the meter says so instead of showing zero.
Set it up
- Choose Add Meter… and pick Disk Space.
- In Customize, choose the volume.
- Pick a face and keep the default alerts or set your own.
Every face works with every source it lists. See all 13 faces running live.
Limits
This is space used, not disk activity (reads and writes per second). Multimeter 1.0 has no disk activity meter.
Questions
Why does my Mac say a different free space number than Terminal’s df?
df doesn’t count purgeable space (like caches macOS can clear) as free. Finder and Multimeter do.