WinDirStat is a free application designed to compile statistics on the space occupied by specific locations on the hard drive. The tool reads the entire directory tree (which may take a few minutes depending on the capacity of the hard drive) and represents them in the same form using the graphical interface. In addition, WinDirStat has the option of previewing the occupied space in the form of a Tree Map, which shows the entire contents of the directory tree in a simple and understandable way.

Each file is represented by a colored rectangle with a surface proportional to the size of the file, and the color of the rectangle determines the file type as shown in the file extension list.