Add the "Folder Size" column in Detailed view of a folder
FolderSize column in Windows Explorer
Folder Size for Windows adds a new column to the Details view in Windows Explorer. The new column shows not only the size of files, but also the size of folders. It keeps track of which folders you view, and scans them in the background so you can see complete size of all files within the folder. It's very useful for cleaning up your disk. Once you get used to having that information available, a directory listing simply looks incomplete without it!
Using one of the above dirsize.dll plugins, you can add the Folder Size column for folders in Detail View. These plugins calculate the folder size and displays the information in a separate column. Place the file in Windows\System32 folder. Now, register the DLL using regsvr32 command from Start, Run dialog.
Next, open a folder and set it to Detail view. From the View menu, click Choose Details. Put a checkmark near Folder Size, and click OK. Use CTRL and + key combination to resize the column width, so that the Folder Size column is displayed correctly.
To apply this setting for all the folder, click Tools, Folder Options. In the View tab and click Apply to all folders.
To remove the feature, simply un-register the DLL [regsvr32 /u %Systemroot%\System32\Dirsize.dll]. Ignore error messages if any.
Moveax - ViewFolderSize
ViewFolderSize helps you view total folder and file sizes directly in the Windows Explorer. With it, you can view file and folder sizes in bytes, kilobytes, megabytes and gigabytes. Developer homepage: Moveax - ViewFolderSize