Originally Posted by Magus2727
Usually there is some indicator on the side of the fan that says AirFlow or Flow with an arrow. Or just power it up and see which direction it flows. Usually but no in all cases if you are looking at the front of the fan that may have a logo or some sort in the middle that is usually the intake so it pushes fan out the back. but that is not always the case, just what I have seen on my fans.
If you are looking at the fan, and you can see the center hub without mount to the frame, the fan blows towards you. And vice versa, if you are facing the fan towards you, and you can see the mounting frame, the fan is blowing air away from you.