Folder Size
This utility scans the selected folder and reports the total size of the files and subfolders it contains, the amount of disk space being wasted, and the amount of actual disk space occupied by the files. It also shows how the folder's size breaks down into percentages between its subfolders. Click any item in the list to see the total number of files and folders it contains, and the size and name of the largest file.You can expand any folder in the tree to see similar percentage details relating to that folder. You can even find the total size of multiple subfolders by simply selecting them and reading the details in the panel below.
Finally, Folder Size can tell you what space is required to copy files to other disks. Although it does its calculations using the actual cluster size of the current disk, you can change this to any cluster size you like and rerun the scan ideal for finding out whether files will fit on a CD-ROM, or to work out how much disk space you'll save by decreasing your disk's cluster size.