DaisyDisk vs OmniDiskSweeper vs GrandPerspective

Checked 13 October 2026 against each developer's own website and documentation, and the Mac App Store. We didn't benchmark scan speed; how fast a scan runs depends mostly on how many files you have.

Do you need one? What Storage settings shows

Start with what's built in. System Settings › General › Storage shows your disk split into categories, and the ⓘ button next to Documents opens views of large files and downloads, plus a file browser you can sort by size (Apple, Change Storage settings). For finding the odd big video or forgotten disk image, that's often enough.

Where it falls short is the in-between: folders. Storage settings tells you that System Data is large, or that Documents is, but not which folder inside your Library or which project folder holds the space. It also can't show you anything inside System Data. That's where a disk analyzer earns its place: it walks every folder it can read and shows you where the space actually is. The full order for freeing up space covers what to do once you've found it.

The three apps

DaisyDisk

DaisyDisk from Software Ambience shows your disk as an interactive sunburst: rings of segments, each sized by how much space it takes, that you click to zoom into (DaisyDisk). It's $9.99 once, for up to five of your personal Macs, with a 30-day money-back guarantee, and it's also on the Mac App Store at the same price. The website version needs macOS 10.13 or later and runs natively on Apple silicon; the App Store version needs macOS 12.

• Trial: the free download from the website isn't time-limited, but it can't delete files and can't scan as administrator. The App Store version has no trial.
• Hidden space: scanning as administrator, in the website version, lets it account for space a normal scan can't see. The App Store version can't do this; DaisyDisk lets App Store buyers switch to the website version free of charge.
• Deleting: you drag items to a "collector" at the bottom and click Delete, with 5 seconds to cancel. DaisyDisk's guide says it removes files permanently instead of moving them to the Trash, so the space is recovered straight away, and that deleted files can't be undeleted (DaisyDisk, Deleting files).

OmniDiskSweeper

OmniDiskSweeper from The Omni Group is the plainest of the three: a list of folders and files sorted by size, which you drill into folder by folder (The Omni Group). It's free; Omni has described it as freeware since 2009. The current download is version 1.16, and a 1.17 test build supports macOS 14 through 27.

• Deleting: since version 1.10, its Delete button moves items to the Trash. Holding the Option key deletes immediately instead (Omni Group blog).
• Good for: people who prefer a sorted list to a picture, and want to see exact sizes at a glance.

GrandPerspective

GrandPerspective, by Erwin Bonsma, draws your disk as a treemap: one rectangle per file, sized by how big it is, grouped by folder (GrandPerspective). It's free from SourceForge, or $2.99 on the Mac App Store; the author says you get the same app either way, and that the fee covers Apple's developer membership. Version 3.8.1 needs macOS 14 or later; version 3.7.2 still supports macOS 11 to 13.

• Deleting: Delete moves the selected item to the Trash. The control is turned off by default, to make accidental deletion less likely.
• Good for: spotting single large files at a glance, since every file is drawn, not just folders.

Side by side

Choose DaisyDisk if you want the most polished visual and the ability to account for hidden space, and you're comfortable with deletion that skips the Trash. Choose OmniDiskSweeper if you want exact sizes in a list and a free tool that uses the Trash. Choose GrandPerspective if you want a free visual map that shows every file.

Reading the results safely

A disk map makes big folders look like easy wins. Some of them are, and some are folders you should never delete from Finder:

• Your Library folder. It's often the biggest thing in your home folder, because it holds app data, mail, messages and caches. Look inside for a specific app's cache or an old app's leftovers. Never delete Library, or whole folders in it such as Application Support, Containers or Keychains.
• The Photos library. It appears as one huge item. Remove photos in the Photos app, never by deleting inside the library package. How to remove duplicates the safe way.
• iCloud Drive. Deleting a file there deletes it from your other devices too. To free local space only, use Remove Download in Finder.
• System folders and other volumes. /System, /Library, /private and the hidden volumes macOS needs aren't yours to clean, even if an analyzer can see them.
• Copies that share space. Files cloned on APFS share storage, so deleting one copy can free less than the size shown.

Whichever app you use, prefer one that moves things to the Trash, wait a day before emptying it, and keep a backup.

Why each app shows a different total

Run all three and you'll get three totals, and none will match Storage settings exactly. That's expected:

• Analyzers add up the files they can read. macOS protects some folders, such as Mail and Messages, and other users' files, so an app without administrator rights or Full Disk Access can't count them. DaisyDisk reports space it can't see as hidden space.
• Time Machine local snapshots and purgeable space aren't files in your folders, so a folder scan doesn't include them, while Storage settings counts some of that space as available. What purgeable space is.
• APFS clones share storage. Two copies of a file on the same volume can take the space of one (Apple Developer, About Apple File System), but an analyzer that adds up file sizes counts both.
• Units differ. Some tools show binary gigabytes (1,073,741,824 bytes) and others decimal ones (1,000,000,000 bytes) (Apple, How storage capacity is measured).

Where Tend fits

Tend's Space Map shows your home folder by size, and you click a folder to look inside. Viewing it is free; with Tend Pro you can move an item to the macOS Trash from there. Some folders are protected because removing them would break your account or apps: your home folder's standard folders, everything directly inside your Library, credential folders such as .ssh, your keychain, iCloud Drive, cloud storage folders and the Photos library. Space Map doesn't scan system volumes or other users' folders, so for a whole-disk view, including hidden space, DaisyDisk or GrandPerspective go further. How Space Map works.

Questions

Related guides

Sources

• Software Ambience, DaisyDisk, Deleting files, trial vs full version and scanning as administrator, checked 13 October 2026
• Apple, DaisyDisk on the Mac App Store, checked 13 October 2026
• The Omni Group, OmniDiskSweeper and OmniDiskSweeper 1.10; OmniDiskSweeper test builds, checked 13 October 2026
• Erwin Bonsma, GrandPerspective and its help on navigating views, checked 13 October 2026
• Apple, Change Storage settings on Mac
• Apple Developer, About Apple File System
• Apple, How storage capacity is measured on Apple devices

DaisyDisk, OmniDiskSweeper and GrandPerspective are trademarks of their owners. Tend isn't affiliated with any of them. Spotted something out of date? Tell us and we'll fix it.