How to Check Storage on Mac (And What It Hides From You)

To check storage on a Mac, open the Apple menu, choose System Settings, click General, then Storage. You get a coloured bar split into categories such as Applications, Documents, Photos and System Data, with a size for each. On macOS 12 Monterey and earlier the same screen is under About This Mac > Storage.

That's the right first stop, and it has a limit: it tells you what kind of thing is using space, not which folder. This guide covers the three built-in ways to check, what each one leaves out, and what to do when the numbers don't add up.

How do I check storage on my Mac?

macOS 13 Ventura and later, including macOS 26: Apple menu > System Settings > General > Storage. You can also get there from Apple menu > About This Mac > More Info > Storage Settings.

macOS 12 Monterey and earlier: Apple menu > About This Mac > Storage tab, then Manage for the breakdown.

Give the panel a minute. macOS recalculates the categories each time you open it, and the figures shuffle while it works. The bar at the top shows used and available space. Below it, each category has a size and an i button that opens a list of what's in it.

How do I see what's taking up space on my Mac?

The category bar tells you the type of file, not the file. To get closer, use these three, in order of how much they show you.

1. The Storage panel's file lists

Click the i next to Documents. A window opens with Large Files, Downloads, Unsupported Apps and File Browser tabs. Large Files is the most useful thing Apple ships for this problem and few people open it: individual files sorted by size, with the date you last opened each one. Select a file and click Delete to remove it.

What it misses: anything inside your Library folder, which is where most of the space usually is, and everything counted as System Data.

2. Finder's Get Info

Select any folder and press Cmd + I. The size appears after a few seconds. To reach hidden folders such as ~/Library, press Cmd + Shift + G and type the path. In list view, View > Show View Options > Calculate all sizes adds a size to every folder in the window so you can sort by it.

What it misses: nothing, in principle. The catch is that you check one folder at a time, and an 80 GB folder buried four levels deep can take twenty minutes of clicking to find.

3. Terminal

For total, used and free space on your startup disk:

df -h /

For the size of one folder:

du -sh ~/Library

To rank everything in a folder by size, largest last:

du -sh ~/Library/* 2>/dev/null | sort -h

What it misses: it's exact and fast, but you still need to know where to look, and a du of your whole home folder prints a wall of text.

Why doesn't the storage bar add up?

The categories in the Storage panel don't add up to the used figure because several of them overlap and one is deliberately vague.

• System Data is the catch-all for everything macOS can't classify: caches, logs, local Time Machine snapshots, app support files, swap. It has no file list and no delete button. On a full Mac it's often the largest segment. See how to clear System Data on Mac.
• iCloud Drive files can show at full size while only a placeholder is stored locally.
• Purgeable space is counted as used even though macOS frees it on demand.
• Other Volumes in Container appears in Disk Utility rather than Storage settings, and it confuses people for a different reason: it's usually your own Data volume. See Other Volumes in Container explained.

So the bar is a rough map, not an inventory. It points you roughly in the right direction and then stops.

What is purgeable space on Mac?

Purgeable space is storage macOS has marked as reclaimable, mostly local Time Machine snapshots, caches and iCloud files that also exist in the cloud. It's counted as used, and macOS releases it automatically when the disk runs short. That's why you can delete a 30 GB file and see free space barely move, or copy a large file onto a "full" drive and have it succeed: the space was there, macOS just hadn't released it yet.

To see the figure, select your startup disk in Finder and press Cmd + I; the Available line shows purgeable in brackets. Disk Utility shows it too when you select the volume. To force some of it back now, thin the local snapshots:

sudo tmutil thinlocalsnapshots / 21474836480 4

That asks macOS to free about 20 GB of snapshot space. A completed Time Machine backup does the same job without Terminal.

How do I check storage from Terminal?

Three commands cover it:

Command	What it tells you
df -h /	Total, used and available space on the startup volume
du -sh ~/Library	The size of one folder
du -sh ~/Library/* 2>/dev/null | sort -h	Everything in a folder, ranked by size

du reports what's on disk and ignores the categories, which makes it the most honest built-in answer. It's also the slowest to read, and it can't see inside local snapshots, so it won't explain purgeable space.

How much storage does macOS take up?

macOS itself takes roughly 12 to 20 GB, shown as the macOS segment in Storage settings. That figure is fixed and you can't reduce it. What grows is System Data, which sits next to it and is often mistaken for the operating system.

Why does my Mac say storage is full when it isn't?

A Mac reports storage as full when purgeable space hasn't been released yet, when local Time Machine snapshots have built up, or when a huge System Data segment is hiding caches and leftovers. Restart, let a Time Machine backup finish, then check the Storage panel again. If it's still full, one of the folders in how to free up space on Mac is the reason.

Seeing the whole drive at once

Each method above answers a narrow question: how much is left, how big is this one folder, what are my largest loose files. None of them shows you the shape of your drive.

That's what DissectMac does. It scans your Mac and draws every folder as a block sized by the space it uses, so "what's taking up my storage" is answered by whichever rectangle is biggest. Click a block to go deeper, or reveal it in Finder. It reads the hidden folders the Storage panel skips, the scan runs entirely on your Mac, and the map is free.