See What's Taking Up Space on Your Mac

Your disk is nearly full and the storage bar isn't saying why. macOS has three built-in ways to break usage down — the storage settings, Finder's size columns, and a one-line Terminal command — plus two free apps that map the whole disk. Work through them in order and the culprit surfaces fast.

Start with the storage settings

Open System Settings → General → Storage and give the numbers a minute to calculate. The color bar at the top shows usage by category, and the category rows beneath it each carry an ⓘ button that opens a size-sorted breakdown. The Documents one is the most useful: its Large Files, Downloads, and File Browser tabs let you inspect — and delete — files right from that window. Storage recommendations (Store in iCloud, Empty Trash Automatically, and the like) sit at the top of the same screen.

Two caveats: the numbers refresh slowly after you delete things, and large "System Data" or "Other Users" segments won't itemize here — more on that below.

Make Finder show folder sizes

1. Open your home folder and choose View → as List.
2. Press Command-J to open View Options and tick Calculate all sizes.
3. Click the Size column header to sort largest-first, then drill into whatever tops the list.

Folder sizes normally show as "--" in list view, which is why this option matters. Apply it per folder, or click Use as Defaults in the same panel to make every list view calculate sizes. For a one-off check, select any folder and press Command-I for Get Info.

Rank folders from Terminal

# Size of every visible top-level item in your home folder
du -sh ~/* | sort -h

# The usual hidden culprits live in ~/Library
du -sh ~/Library/* | sort -h | tail -15

The first time Terminal touches Desktop, Documents, or Downloads, macOS shows a permission prompt — that's the standard privacy protection, and it's fine to allow. These commands only measure; nothing here deletes anything, so there's no undo to worry about.

For the headline number, df -h / prints the disk's total, used, and available space. Don't be surprised if it disagrees with Finder by a few gigabytes — Finder counts purgeable storage as available, while df reports what's physically free right now.

Free visualizers for the whole disk

Two free utilities finish the job. OmniDiskSweeper presents every folder as a size-sorted list you can drill into, and GrandPerspective draws a treemap where every file is a rectangle scaled to its size — a lone 40 GB virtual machine or a forgotten video project jumps out instantly. Grant either app Full Disk Access in System Settings → Privacy & Security → Full Disk Access if you want complete numbers, and flip that permission back off there once you're done.

The usual suspects, once you can see them

Whatever tool you use, the same offenders top the list on most Macs: a Downloads folder full of installers and disk images, old iPhone or iPad backups under ~/Library/Application Support/MobileSync, developer caches in ~/Library/Developer if Xcode has ever been installed, a Photos or media library that outgrew the disk, and a Trash nobody has emptied in months. Measure first, though — deleting by guesswork is how people remove the wrong 200 MB while a 60 GB folder sits untouched one level deeper.

When the answer is "System Data"

If the storage bar blames a giant System Data segment rather than your own files, you're looking at caches, snapshots, and logs — see what System Data is and how to shrink it.