TreeSize tells you how your disk space is being used. It can be started from the context menu of a folder or drive and shows you the size of the selected folder, including its subfolders. Each folder can be expanded in Explorer-like manner to view the size of its subfolders. Scanning is done in a thread, so you can already see results while TreeSize is working without having to wait.
The results can be printed in a report. This version is a slimmed down, but fully functional and free version of TreeSize Pro and does not offer the graphical pie charts.
TreeSize, Freeware, Software, Download