MemoryPeek: Is Your Mac Out of Memory?

How to use MemoryPeek to tell whether your Mac is really short of memory: memory pressure, where RAM goes, swap and the apps using the most.

The question it answers: is my Mac actually running out of memory?

What you see

Memory pressure, as a gauge: Normal, Warning or Critical, with a note in plain words. Pressure is what tells you whether memory is short. A Mac whose memory looks “full” is usually fine, because macOS keeps spare memory busy with cached files on purpose.
Memory in use, as a ring, and a chart of it since you opened the screen.
How memory is used: app memory, wired (kept by macOS), compressed, cached files (given back as soon as an app needs room) and free, as a colour bar and in GB.
Moved to disk (swap): how much memory macOS has written to disk. Some swap is normal while pressure stays normal.
Using the most memory: the 15 apps with the largest memory footprint, the figure Activity Monitor’s Memory column shows.

The launcher shows a Memory ring with memory in use, for example “71%” and “17 / 24 GB”. It turns red when pressure is critical.

Open MemoryPeek and read the pressure gauge and the note under it first.
If pressure is Warning or Critical, look at the apps using the most memory and quit the ones you do not need.
Leave the screen and reading stops. Coming back starts from a fresh reading.

MemoryPeek explains memory; it never “frees” or “cleans” it. There is no purge button, by design.
Other users’ and protected processes, including some macOS services, cannot be read, so they are not listed.
The split follows the commonly documented mapping of macOS’s memory counters; Activity Monitor’s exact arithmetic is not public, so small differences are possible.

Read-only; nothing is stored or sent. It needs no permission. See permissions.