How to check RAM usage on a Mac

How much memory does your Mac have?

Choose Apple menu → About This Mac. The Memory line shows the total. On Apple silicon Macs this memory is shared between the processor and graphics, and can’t be upgraded later.

See what’s using it

1. Open Activity Monitor (press ⌘ Space and type its name).
2. Click the Memory tab.
3. Click the Memory column header to sort apps by how much they use.

What the numbers mean

Physical Memory

The total installed.

Memory Used

The sum of app memory, wired memory, and compressed memory. It’s normal for this to be high.

App Memory

Used by apps and their processes.

Wired Memory

Reserved by macOS itself; it can’t be compressed or swapped.

Compressed

Memory macOS has squeezed to make room instead of writing it to disk.

Cached Files

Recently used files kept in memory to open faster. macOS gives this back the moment apps need it.

Swap Used

Memory written out to your disk because there wasn’t room. A little is normal; gigabytes that keep growing mean you’re short.

Memory Pressure

The graph that sums it all up: green is fine, yellow is working hard, red means the Mac is short of memory.

Unused memory is wasted memory, so macOS fills it with caches. Judge by memory pressure and swap, not by “Memory Used”. More in what memory pressure means.

From Terminal

For a quick snapshot, these built-in commands work in any Terminal window:

memory_pressure | tail -1
sysctl vm.swapusage
top -l 1 -o mem -n 10 -stats pid,command,mem

The first prints the percentage of memory that’s free, the second shows swap, and the third lists the ten processes using the most memory.

If one app uses too much

Browsers are the usual suspect: each tab and extension runs in its own process, so the total is spread over many “Helper” entries. Close tabs you don’t need, and restart apps that have been open for days, since some slowly grow over time. See why your Mac is using so much RAM.