Folder Size Explorer is described as 'simple and free Windows Explorer clone with the added ability to calculate folder sizes' and is an app in the File Management category. There are more than 10 alternatives to Folder Size Explorer for a variety of platforms, including Windows, Linux, Windows S, Mac and BSD. The best alternative is WinDirStat, which is both free and Open Source. Other great apps like Folder Size Explorer are TreeSize (Paid), Baobab Disk Usage Analyzer (Free, Open Source), MindGems Folder Size (Free) and crossdirstat (Free, Open Source).
TreeSize Professional tells you where precious disk space has gone to. It can be started from the context menu of a local folder or a local drive and displays the size of each folder, including its subfolders.
Baobab Disk Usage Analyzer is a graphical application to analyse disk usage in any Gnome environment. Disk Usage Analyzer can easily scan device volumes or a specific user-requested directory branch (local or remote).
Free open-source cross-platform file & directory statistics as found on Github - Generate a directory tree for any given folder - View any folder as colored rectangles (squarified algorithm) - Customize the rectangle colors and show statistics about filetypes - Export...
Folder Size Catalog provides at-a-glance view of your folders and folder sizes so that you can easily check the distribution of your disk space. Fast search and index Fast and efficiently searches through folders and recursively through all component subfolders.