How to see which app is using the most memory on a Mac

27 October 2026 · 5 min read

To see which app is using the most memory on a Mac, open a process list that shows memory per app and sort it by the Memory column, largest first. Foreman does this in its Processes page, and Terminal can do it with one command. The part people miss is that many apps run as several processes, so the biggest single line is often not the biggest app until you add the helpers up.

Here is how to read the list, what counts as a lot, and what to do once you have found the culprit.

Option 1: Foreman, sorted by Memory

Press Control-Shift-Escape from any app to open Foreman, or click its readout in the menu bar and choose Open Foreman. On the Processes page, click the Memory column header to sort by memory.

Two things make this page easier to read than a raw list. First, apps are grouped with their helper processes, and the memory of the helpers is added into the app’s row. Open the row to see the individual pieces. Second, many macOS background programs have plain-English names, with the real name beside them in grey, so you can tell what you are looking at.

Above each column is the figure for the whole Mac, so you can see how big a single app’s share is. The Performance page also has a Memory section that lists the apps using the most memory, with End Task and Efficiency Mode.

Option 2: Terminal

If you would rather not install anything, Terminal can list processes by memory. This shows the ten largest at one moment:

top -o mem -l 1 -n 10 -stats pid,command,mem

The -stats part keeps just three columns: the process ID, the name and MEM, the memory each process is holding. The command only reads and then exits. The catch is that you are looking at one process per line, with no grouping, and long names are cut short, so a browser appears as several separate lines with the same clipped name. You have to add them up yourself.

Why helper processes change the answer

Most browsers, chat apps and editors split their work into several processes: one for the main window, others for each tab or extension, others for graphics and networking. A browser with twenty tabs can show twenty or more lines, each of them modest, which together outweigh everything else on the Mac.

Safari’s pages run as separate web content processes, which Foreman labels “Web content”. Other browsers use their own helper names. What are helper and renderer processes on a Mac explains what each kind does.

So when you scan a flat list, ask a different question. Instead of “which line is biggest”, ask “which app owns the most lines”. If the top line is 800 MB but one app owns fifteen lines of 300 MB each, the app is the real answer.

What counts as a lot

There is no single number, because a lot depends on how much memory the Mac has. These are rough guides, not rules, and they work best as a share of the whole:

An app holding a few hundred megabytes is ordinary. Most everyday apps live here.
An app holding several gigabytes on a Mac with 8 GB or 16 GB is a large share, and worth a closer look.
One app holding more than a quarter of the Mac’s memory is worth a closer look on any Mac.

Creative and developer tools, such as video editors, photo editors, virtual machines and code editors with big projects, legitimately use several gigabytes. That is not a fault. The question is whether the amount matches the work you are doing in it.

Also remember that a large figure is not a problem on its own. What matters is whether the Mac is short of memory. Memory pressure on a Mac: when you actually need more RAM shows how to tell.

What to do about the biggest app

Work down this list and stop when the Mac feels better.

Is it an app you are using? If yes, and it is doing heavy work, leave it. It may just need memory.
Quit it properly. In Foreman, End Task asks the app to quit the way Command-Q does, so it can offer to save your work. Use that first rather than Force Quit.
Reopen it fresh. Apps that have been running for many days often hold more memory than they did when they started. Quitting and reopening gives it back. Foreman’s Restart does both in one step and reopens the app behind Foreman so you stay where you were.
Trim what it is holding open. For a browser, that means closing tabs and windows. For an editor, closing projects you are done with.
If you need it open but not right now, use Efficiency Mode. While the app is in the background it runs at background priority and in short bursts, and at full speed when you are in front of it. This lowers its processor use. It does not release its memory, so choose it for a busy app, not for a large one.

Force Quit is on the right-click menu of an app in Foreman, and the Force Quit window (Option-Command-Escape) is macOS’s own way to the same job. Force Quit loses any unsaved changes, so Foreman asks first on an app with windows.

Check what is running when you are not looking

If memory is high and you cannot see the cause among the apps you opened, sort again and read the Background processes section. Items that start themselves at login, such as sync tools and updaters, can hold memory all day. How to find out what’s running in the background on your Mac shows how to go through them.

The short version

Sort by Memory, add the helper processes to their app, and compare the total with how much memory the Mac has. If one app owns a large share, quit it properly, reopen it, and trim what it holds open. If no app stands out and the Mac is slow, the cause is probably somewhere else.