Win7 is pathetic when it comes to calculating folder size.

I quick google search shows general dis-satisfaction with this lack of functionality in WIn7.

Fortunately I can use du.exe from sysinternals suite.

http://technet.microsoft.com/en-us/sysinternals/bb842062.aspx

Usage:

C:\Users\lvhall>D:\software\SysinternalsSuite\du.exe

Du v1.5 – report directory disk usage
Copyright (C) 2005-2013 Mark Russinovich
Sysinternals – www.sysinternals.com

usage: D:\software\SysinternalsSuite\du.exe [-c[t]] [-l <levels> | -n | -v] [-u] [-q] <directory>
-c Print output as CSV. Use -ct for tab delimiting.
-l Specify subdirectory depth of information (default is one level).
-n Do not recurse.
-q Quiet (no banner).
-u Count each instance of a hardlinked file.
-v Show size (in KB) of all subdirectories.

CSV output is formatted as:
Path,CurrentFileCount,CurrentFileSize,FileCount,DirectoryCount,DirectorySize

Example:
C:\Users\lvhall>D:\software\SysinternalsSuite\du.exe -l 1 C:/users/lvhall

Du v1.5 – report directory disk usage
Copyright (C) 2005-2013 Mark Russinovich
Sysinternals – www.sysinternals.com

0 c:\users\lvhall\.android
1 c:\users\lvhall\.p4merge
23 c:\users\lvhall\.p4qt
7,060,698 c:\users\lvhall\AppData
67 c:\users\lvhall\Contacts
4,020,000 c:\users\lvhall\Desktop
86,487 c:\users\lvhall\Documents
6,120,905 c:\users\lvhall\Downloads
4 c:\users\lvhall\Favorites
0 c:\users\lvhall\InstallAnywhere
2 c:\users\lvhall\Links
0 c:\users\lvhall\Music
99,745 c:\users\lvhall\Perforce
614 c:\users\lvhall\Pictures
0 c:\users\lvhall\Roaming
0 c:\users\lvhall\Saved Games
2 c:\users\lvhall\Searches
0 c:\users\lvhall\Videos
Files: 33728
Directories: 4179
Size: 17,813,115,106 bytes
Size on disk: 17,916,833,088 bytes

Example redirecting to CSV file:

C:\Users\lvhall>D:\software\SysinternalsSuite\du.exe -c -l 1 C:/users/lvhall > du.csv