To view the size of the main folders can be seen here, however, the system cannot determine the media characteristics. How to find large folders in Windows 10/8/7 using WizTree. Although Windows 10 has the ability to view the classified media capacity, the Explorer does not intuitively see that the space occupied by each folder is a shortboard. How to show folder sizes in Windows. Folder Size Explorer runs on any recent version of Windows (although I only have it installed on my Windows 7 machine). Just go to the website and click the “Download” tab and you’ll see the link to download the file in.zip format. You can extract the files from the zipped folder and run Setup. Popup windows frequently cover up Explorer’s Close button. This can make you re-size the pop-up windows to adjust your visibility of File Explorer details. So the above two ways should suffice enough to view folder size with ease in Windows XP, Vista, 7 and 8. The above program also works for both 32 bit and 64 bit OS. Folder Size is a freeware Windows utility that adds a new column to the Details view in Windows Explorer for Windows XP. The new column not only shows the size of files, but also shows the size of folders.