8 Best Free Disk Space Analyzer Tools

Free software for finding the largest files on a hard drive

Ever wonder what's taking up all your hard drive space? A disk space analyzer tool, sometimes called a storage analyzer, can scan your computer and then generate a report detailing everything that uses disk space—like saved files, videos, program installation files, and more.

Use one of these tools to figure out why your hard drive, flash drive, or external drive is filling up. Some of them even let you remove files directly from the program.

If you just need to see the amount of used/free space on a hard drive, you can use your operating system's built-in tools, without having to install one of the programs listed below. Learn how to check free hard drive space in Windows, or how to check your storage on a Mac to do that.

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Disk Savvy

Disk Savvy analysis in progress
What We Like
  • Easier to use than most disk space analyzers.

  • Categorizes files in several ways.

  • Regular updates to newer versions.

  • Scan multiple locations simultaneously.

  • Export results to a report file.

  • Works within File Explorer.

What We Don't Like
  • Some features require the paid Pro edition.

  • Only 500,000 files per scan.

We list Disk Savvy as the No. 1 option because it's user-friendly and full of useful features that will help you free up disk space.

You can 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 use the most storage. You can also examine a list of the top 100 biggest files or folders and export the list to your computer to review later.

There's a professional version available, too, but the freeware edition seems perfect. Install it on Windows 11 through Windows XP, as well as on Windows Server 2022–2003.

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Windows Directory Statistics (WinDirStat)

WinDirStat in Windows 8
What We Like
  • Scan a whole drive or a single folder.

  • Provides unique ways to visualize disk space.

  • Can configure commands to delete data.

What We Don't Like
  • Unable to save scan results to a file you can open later.

  • A bit slower at scanning than similar tools.

  • Runs only on Windows.

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

Create your own custom cleanup commands to do things quickly, like moving files off the hard drive or deleting files of a certain extension in a selected folder. You can also scan different hard drives and folders at the same time, as well as see which file types use the most space.

You can install WinDirStat only in the Windows operating system. Windows 95, Windows 98 SE, Windows ME, Windows NT4, etc., up through Windows 11 should work.

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Disktective v6.0 in Windows 8
What We Like
  • Portable.

  • Scans large files in a specific folder or the whole drive.

  • Provides two ways to view disk space usage.

  • Export the results to a file.

What We Don't Like
  • Unable to delete files directly from the program.

  • Exported results are hard to read.

  • Only Windows users can install.

  • An update hasn't been released since 2010.

Disktective is portable and takes up less than 1 MB of disk space, so you can carry it with you on a flash drive.

Each time it opens, you're asked what directory to scan. You can choose any folder on any hard drive that's plugged in, including removable ones, as well as the entire hard drives.

The left panel of the program shows the folder and file sizes in a familiar File Explorer-like display, while the right side displays a pie chart for visualizing each folder's disk usage.

Disktective is relatively user-friendly, 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 or files from within the program, and the size units are static, meaning they're all either in bytes, kilobytes, or megabytes (whatever you choose).

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JDiskReport v1.4.1 in Windows 8
What We Like
  • Shows disk space usage in five perspectives.

  • Interface is ideal for new users.

  • Works on Windows, macOS, and Linux.

What We Don't Like
  • Doesn't let you delete files from within the results.

  • Noticeably slower than other disk space analyzers.

JDiskReport displays file storage in list view or via a pie chart or bar graph. A visual of disk usage helps you understand how the files and folders behave in relation to the available space.

In the left pane, you'll find the folders that were scanned, while the right pane displays ways to analyze that data. You can't delete files from within the program, and the time it takes to scan a hard drive seems slower than some other applications in this list.

Windows, Linux, and Mac users can use JDiskReport.

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TreeSize Free

TreeSize Free v4.0.0 in Windows 8
What We Like
  • Lets you remove files from within the program.

  • Scan individual folders and entire hard drives.

  • Supports internal and external hard disk drives.

  • Portable option available.

What We Don't Like
  • Doesn't work on Linux or macOS.

  • Filtering options aren't super helpful.

  • No unique perspectives are available as with similar tools.

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 lets you see which folders are largest and which files among them are using up most of the space.

If you find 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 and flash drives without installing it to the computer. Only Windows can run TreeSize Free.

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RidNacs v2.0.3 in Windows 10
What We Like
  • Minimal and simple interface.

  • Portable option available.

  • Scans large files in a specific folder or the whole drive.

What We Don't Like
  • Won't run on Linux or macOS.

  • Missing advanced features found in similar applications.

RidNacs is for the Windows OS, and while it's similar to TreeSize Free, it 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 or scan 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.

Open the folders as you would in File Explorer to see the folders or files listed in descending order. RidNacs 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 such as WinDirStat.

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SpaceSniffer v1.3 in Windows 8
What We Like
  • Results can be filtered several ways.

  • Results can be backed up and opened again without rescanning.

  • Delete files from inside the program.

  • Report of large files can be saved to a text file.

  • Completely portable.

What We Don't Like
  • Can be hard to grasp at first.

  • Works only on the Windows operating system.

Most of us are used to viewing the data on our computers in a list view; however, SpaceSniffer uses blocks of varying sizes to demonstrate folder and file sizes.

Right-clicking any folder or file in SpaceSniffer opens the same menu that you see in File Explorer, meaning you can copy, delete, and perform other file functions. The filter feature lets you search through the results by file type, size, or date. You can export the results to a TXT file or a SpaceSniffer Snapshot file.

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Folder Size

Folder Size v2.6 in Windows 10
What We Like
  • Integrates with File Explorer.

  • Sort folders by size.

  • Extremely user-friendly.

What We Don't Like
  • Shows results in an extra window instead of the window you're viewing.

  • Runs only on Windows.

  • Long time since the last update.

This disk space analyzer is useful since File Explorer only provides the size of the files, instead of the size of the folders. With Folder Size, you can see the size of each folder in a small window. In this window, you're able to sort the folders by size to see which ones use the most storage.

In the app's settings, you can disable CD and DVD drives, removable storage, or network shares.

The user interface is nothing like the other analyzers in this list. If you don't need charts, filters, and advanced features, and only want to sort folders by size, this program will do just fine.

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