How to Show the Size of Folders in Mac OS X List View
STEP 1. From a Finder window, simply select list view.
STEP 2. Now from the View menu, select “View Options” or you can click Command+J.
STEP 3. Now simply select the checkbox next to “Calculate all sizes” as shown in the image below.
That’s it. Now you will be able to see the size of folders and their respective contents in Mac OS X list view. In this way you can show the size of folders in Mac OS X list view. If you found any difficulty in following steps then feel free to ask in the comment section below.