Judging from the picture, it appears to be shorter in height than width. I would believe the 13-1/2" width measurement because of the way a folder fits into it, assuming the folder is a standard size. But the tabs of the folder would not be sticking out the top of the pocket if the height is truly 20-1/2". It must be shorter than this, I'm guessing around 8-9". That's a big difference when you are deciding how many to order.