See the size of every folder on your disk.

(1) Download Folder Sizes. (Requires Java.)
(2) Click "Start" to install Folder Sizes. More...
(3) Click the top-left button to choose a different root folder to scan.
(4) Folder Sizes shows the cumulative size of all the files in the chosen folder and its subfolders.

The "size" shown for a folder includes all of its files and subfolders.

And the tooltip tells you the last time anything in that folder was changed.

Scanning is done in the "background", so you can browse the current display while you wait.

When you open Folder Sizes, it rescans whatever folder you were looking at last time.

Note: Folder Sizes will need your permission to read the sizes of files on your disk. More...

Doesn't Folder Sizes just duplicate what Windows Explorer already does?

Partly. Windows Explorer can calculate folder sizes, but only one at a time in their properties dialog. And Explorer's "modified" date is simply the day the folder was created, and has nothing to do with the contents of the folder.

Nevertheless, Windows Explorer has some other features which make it a useful supplement to Folder Sizes. ;-)

Doesn't Folder Sizes just duplicate what the Macintosh Finder already does?

Partly.  Under the Finder's "View Options" you can check "Calculate folder sizes".  But using Folder Sizes is faster.

And although the Finder's "date modified" tells you the last time something was added to or removed from that folder, it tells you nothing about the dates on the files or subfolders it contains. [Is this still true for Mac OS X?]

Why does Java give a "Security Warning" when I install?

Folder Sizes needs to access your hard drive (more)

Why does Folder Sizes need access to my hard drive?

Folder Sizes reads the size and last-modified date of every file in the folder you specify, including all subfolders.

LINKS

Check out JDiskReport; a similar utility with more features.