View Folder Size Pro (formerly TotalSize) is a handy add-on for Windows Explorer, that enables you to add a new column to the detailed file view, that displays the total size for folders as well as files. While Windows shows you the size for all files, it does not show the size for folders - this little program can overcome the limitation. In addition, it includes and Internet FileSize tool that enables you to get the file size, redirection URL and estimated download time for most download links, without having to download the file first.

The license of this software is Free Trial Software, the price is $24.95, you can free download and get a free trial.