Below is a list of my top picks for free disk space analyzer tools, sometimes called storage analyzers. After experimenting with several of these apps on my computer, I can confirm that the apps listed here are 100% free to use and do an excellent job of figuring out what’s filling up a hard drive, flash drive, or external drive. Some even let you delete files right from the program.

I'm putting Disk Savvy at number 1 because it's easy to use and packed with useful features that have helped me free up disk space several times over the years.

You can check internal and external hard drives, search through the results, delete files from the program, and group files by extension to see which file types are using the most storage space. You can also browse a list of the top 100 largest files or folders and export them for later viewing.

There is also a professional version available, but the freeware edition seems perfect. I am using it on Windows 11, but it works for versions up to Windows XP, plus Windows Server 2022–2003.