WhatSize: Tom's Mac Software Pick

Multiple Data Views Let You Free Up Drive Space Quickly

WhatSize Sunburst graph
Screen shot courtesy of Coyote Moon, Inc.

It can be frustrating to try to make room on your Mac when it reports that one of your drives is getting a bit too full. Deleting the trash will usually free up a bit of room, but if your drive is really overflowing, the cleanup process has only just begun, and tracking down which files and folders are using more than their fair share of space can be a daunting task.

That’s where WhatSize comes in. Created by the folks at ID-Design, WhatSize provides the tools needed to measure the size of every item stored on your Mac, and then display the information in multiple views. Each view provides new ways to look at the data, and determine where you can pare down the bulk that's stored on your Mac’s drive.

But WhatSize doesn’t stop with showing you the inner details of your drive. It includes utilities that can help you remove files, find duplicates, and even remove localization files that many apps include.


  • Can examine and display size information for any drive connected to your Mac.
  • Offers multiple views: Browser, Outline, Table, and PieChart.
  • Includes three utilities to help in the cleanup process: Cleaner, Delocalizer, and Duplicates.
  • Easy-to-use interface.


  • Initial scan or re-measure can be slow, depending on drive size.
  • Cleaner tool is basic; it only examines preset locations for items to delete.

WhatSize offers some of the best analysis tools I’ve seen in an app that explores drives for files and folders to remove. The various views, and its ease of use are what make WhatSize a real standout.

Which WhatSize

WhatSize is available in two forms; the first is available from the Mac App Store and the second directly from the developer. Although the Mac App Store version is less expensive, it also doesn't have as many features as the version sold directly by the developer. The Mac App Store version is also a major version release behind the version available directly from ID-Design.

This review will look only at the version available directly from the developer, currently at version 6.4.2.

Installing WhatSize

WhatSize is provided as a .dmg file. Double-click the .dmg file, and your Mac will mount a disk image that contains the WhatSize app. Once the disk image opens, simply drag the app to your Applications folder.

Using WhatSize

WhatSize opens to a multi-pane window that includes a toolbar across the top containing just about everything you need. The only trip I made to the WhatSize menus was for a peek at the help file, to see how extensive it was.

By the way, I recommend a read through the help file. It's well written, and shows off many of the app's capabilities, which you might not otherwise know are there.

The left-hand sidebar contains all of the devices; essentially, the drives connected to your Mac. In addition, there's a Favorites section, which contains some commonly used folders, such as Desktop, Documents, and Music. You can add or remove items from the Favorites section, which allows you to customize the sidebar to suit your needs.

WhatSize Views

The views are what set WhatSize apart from similar apps. There are four views available: Browser, Outline, Table, and PieChart. Each view presents the data (files and folders) stored on the selected device a bit differently, and each view can be helpful for discovering large chunks of data you may no longer need.

The Browser view is a lot like the Finder's column view; it lets you work your way through the hierarchy of a drive or folder. The Outline view is more like the Finder's list view, showing details about each item.

The Table view may be the most versatile because it includes a search function that allows you to narrow down your search. For instance, you may want to find files that haven't been used in over 6 months and are larger than 100 MBs.

The last view is the PieChart, also known as a sunburst chart. WhatSize’s PieChart view offers a way to see how data is stored on the drive. Working out from the center, the PieChart shows concentric rings, each corresponding to the hierarchy of folders. Those at the center are closer to the root entry point of the drive; as you move out through the rings, you move folder by folder away from the root point.

The PieChart is interesting, and it does provide a visual clue about both the size and location of a file or folder, but I thought the other views were actually more useful in finding files or folders to remove.

Removing Files and Folders

From the various views, you can select an item, and then right-click it and send it off to the trash. Right-clicking an item also brings up many additional commands, including revealing the item in the Finder, a nice way to take a closer look at a file.

By the way, the Finder's Quick Look feature works within the various views, so selecting a file and pressing the spacebar will reveal the file's contents in a Quick Look window. However, using this method, you're basically removing files one at a time, a bit of a pain if you have a lot of space to free up.

Cleaner, Delocalizer, and Duplicates

WhatSize has three built-in utilities for quickly finding files to remove.


Cleaner provides quick access to log files, the downloads folder, cache files, NiB files, localized files, and known temporary folders, allowing you to quickly delete their contents.

Developers commonly use NiB files to present an alternate user interface layout. An example would be a word processor interface, with the layout altered a bit to accommodate another language.

Localized files are additional data files used by an app to support multiple languages.

Cache files are used by the Mac to speed up certain processes; many apps also use cache files. Removing them can slow things down a bit, but will temporarily give you a bit of free space. It’s only temporary because the cache files are recreated as soon as they're needed.

I didn’t find Cleaner to be very useful. In fact, if the files the Cleaner can remove are enough to temporarily fix my space needs, then I'm in real trouble and will need to consider a larger storage system made up of bigger drives or additional external storage.


The Delocalizer tool can search a drive for system and application localization files. The idea is that you probably won’t need to use an app in all of the languages available, so removing those you don’t need will free up space.

The problem is that just like the Cleaner tool, if your drive is so full of information that removing the localization files can provide temporary relief, then you have bigger worries than what this tool can remove. You need additional storage space; removing these files won’t help all that much.


Duplicates may be the best of the utilities included with WhatSize. The Duplicates tool looks at a file's content, creates a signature that represents the file, and then compares it to similar files it finds.

Using the signature method allows Duplicates to find files that have the same content, even if the file names are different.

You can delete the duplicate immediately, move it to the trash, or replace the duplicate with a hard link to the original.

Final Thoughts

WhatSize is very helpful for tracking down files to delete in order to free up space on Mac’s drive. Its various views allow for both different ways to see data and different tools for tracking down data to eliminate.

I found two of the utilities for helping track down data, Cleaner and Delocalizer, a bit less than useful, not because they don’t work, but because their impact on drive space would largely be temporary. A better approach would be to invest in more storage space, either a bigger drive or additional external storage.

The rest of WhatSize is very useful for cleaning up a drive, as well as keeping track of what’s going on with your Mac's storage space.

WhatSize is $29.99. A demo is available.

See other software choices from Tom's Mac Software Picks.