A pleat counter and methods are provided to accurately count the number of pleats in a corrugated sheet of material to be used for the production of air filters. The pleat counter comprises a pleat detector mounted underneath a mounting board for counting the pleats. The mounting board is configured to position the pleat detector adjacent to the corrugated sheet of filter material. The pleat detector includes one or more sensors configured to detect the presence of individual pleats comprising the corrugated sheet. The pleat counter includes an interface configured to enable coupling the pleat counter with a data processing system. The data processing system may comprise any of a desktop, a tablet, a server, a mobile phone, a media player, a personal digital assistant (PDA), a personal communicator, a network router or hub, a wireless access point (AP) or repeater, a set-top box, or a combination thereof.