Abstract: Most Diazo printers and other such copy machines have an automatic feed capability provided by a drive roller for receiving light-sensitive paper from copy paper rolls of varying widths and feeding the paper into the machine. To provide a square footage count of the machine output, a measuring wheel is mounted to ride on the drive roller and be driven by its contact with the copy paper. The wheel roller which carries a small magnet is disposed closely adjacent to a magnetic switch so that, once during each roller revolution, the magnet closes the switch and closes a power circuit coupled to a counter. The diameter or circumference of the wheel roller is preselected so that each of its revolutions represents one square foot of the copy paper on which it rides. Preferably, there are provided a plurality of wheel rollers each of which has a diameter matching that of various copy paper widths for which the machine is adapted.