9 Best Free Disk Space Analyzer Tools

We list Disk Savvy as the No. 1 disk space analyzer program because it's both easy to use and full of useful features that are sure to help you free up disk space.

Analyze internal and external hard drives, search through the results, delete files from within the program, and group files by extension to see which file types are using the most storage.

Examine a list of the top 100 biggest files or folders. You can even export the list to your computer to review them later.

There's a professional version of Disk Savvy available, too, but the freeware version seems perfect. Install Disk Savvy on Windows 10 through Windows XP, as well as on Windows Server 2016/2012/2008/2003.

WinDirStat ranks right up there with Disk Savvy in terms of features—we're just not too fond of its graphics.

Create your own custom cleanup commands. These commands can be used from within the software at any time to do things quickly, like move files off the hard drive or delete files of a certain extension that are in the folder you select.

You can also scan different hard drives and folders all at the same time as well as see which file types are using up the most space, both of which are unique features not found in all of these disk usage analyzers.

Install WinDirStat in the Windows operating system only.

Another free disk space analyzer, JDiskReport, shows how files are using storage through either a list view like you're used to in Windows Explorer, a pie chart, or a bar graph.

A visual take on disk usage helps you understand how the files and folders behave in relation to the available space.

One side of the JDiskReport program is where you find the folders that were scanned, while the right side provides ways to analyze that data.

You cannot delete files from within the program, and the time it takes to scan a hard drive seems slower than some of the other applications in this list.

Windows, Linux, and Mac users can use JDiskReport.

The programs mentioned above are useful in different ways because they provide a unique perspective for you to look at the data. TreeSize Free isn't so helpful in that sense, but it certainly provides a feature that's missing in Windows Explorer.

Without a program like TreeSize Free, you really don't have an easy way to see which files and folders are occupying all the disk space. After installing this program, seeing which folders are largest and which files among them are using up most of the space, is as easy as opening the folders.

If you find some folders or files that you no longer want, delete them from within the program to free up that space.

Get a portable version that runs on external hard drives, flash drives, etc. without installing it to the computer. Only Windows can run TreeSize Free. 

RidNacs is for the Windows OS and is similar to TreeSize Free, but just doesn't have all the buttons that may drive you away from using it. Its clear and simple design makes it more appealing to use.

Scan a single folder with RidNacs as well as whole hard drives. This is an important feature in a disk analyzer program because scanning an entire hard drive may take a long time when you really just need to see the info for one folder.

RidNacs' functionality is straightforward so you know exactly how to use it right from the start. Just open the folders like you would in Windows Explorer to see the largest folders/files listed from the top down.

RidNacs just includes the basic features necessary for what a disk analyzer should have, but it lacks the features you'd find in a more advanced program like WinDirStat from above.

Free Disk Analyzer is a really great free disk space analyzer. We like how simple and familiar the interface is, but there's also some really useful settings worth mentioning.

One option makes the program only search for files if they're larger than 50 MB. If you have no intention deleting files smaller than that, then drastically clean up the results list by enabling this filter.

There's also filtering options so that only music, video, document, archive files, etc. are shown instead of every single type of file.

The Largest Files and Largest Folders tabs at the bottom of the Free Disk Analyzer program provide a quick way to go over what's eating up all the storage in the folder (and its subfolders) you're looking at. Sort the folders by the folder size and location, as well as by the average file size in that folder plus the number of files that the folder contains.

Though you can't export the results to a file like most disk space analyzers allow, we still recommend taking a look at Extensoft's program before you move on to the other applications in this list.

Free Disk Analyzer is available for Windows only.

Disktective is another free disk space analyzer for Windows. This one is completely portable and takes up less than 1 MB of disk space, so you can easily carry it with you on a flash drive.

Each time Disktective opens, it asks what directory you want to scan. You can pick from any folder on any hard drive that's plugged in, including removable ones, as well as the entire hard drives themselves.

The left side of the program shows the folder and file sizes in the familiar Windows Explorer-like display, while the right side displays a pie chart so you can visualize each folder's disk usage.

Disktective is easy enough to use for anybody, but it's hindered by a few key limitations: The export-to-HTML feature doesn't produce a very easy-to-read file, you can't delete or open folders/files from within the program, and the size units are static, meaning they're all either in bytes, kilobytes, or megabytes (whatever you choose).

Most of us are used to viewing the data on our computers in a list view where we open folders to see the files inside. SpaceSniffer works similarly but not in the same way, so it may take some getting used to before you're comfortable with it. It uses blocks of varying sizes to demonstrate larger folders/files versus smaller ones, where the brown boxes are folders and the blue ones are files (you can change those colors).

The program lets you export the results to a TXT file or a SpaceSniffer Snapshot file so that you can load it up on a different computer or at a later time and see all the same results—this is really handy if you're helping someone else analyze their data.

Right-clicking any folder or file in SpaceSniffer opens the same menu that you see in Windows Explorer, meaning you can copy, delete, etc. The filter feature lets you search through the results by file type, size, and/or date.

We've added SpaceSniffer to this list because it's different from the majority of these other disk space analyzers, so you may find that its unique perspective aids in helping you quickly find what's using up all the storage space.