# determine size of a given folder in MBytes  
import os  
# pick a folder you have ...
folder = 'D:zz1'
folder_size = 0
for (path, dirs, files) in os.walk(folder):
for file in files:
filename = os.path.join(path, file)
folder_size += os.path.getsize(filename)  
print "Folder = %0.1f MB" % (folder_size/(1024*1024.0))