Windows Explorer does shows file sizes in a folder/directory when you sort them by size but that’s not the case with folders and sub-folders in each of them, in my case I download lot of compressed files and extracts them to their respective folders that means my Downloads folder ends up with zip,rar files along with theirs extracted folders, I want to view all sub-folders sizes in Downloads folder to know which occupied most space which explorer doesn’t offers, FldrSize is freeware portable folder size viewer for Windows that calculates sizes of all sub-folders in the folder you specified and displays them on its main window.
Download the program zip file, extract its contents to a folder and run the executable FldrSize.exe. Browse for the folder and specify it, the tool calculates and displays all sub folders sizes in quick time. By default program displays sub folders sizes in KB which you can view in MB by selecting MB from options>Size Unit.
FldrSize works on Windows XP/Vista/7.