Abstract: The present invention 10 discloses a device for counting the repetitions of various types of exercise machines 12. A permanent magnet 14 is attached to a movable member, e.g., a weight stack 16, of the exercise machine 12 selected so as to move within an acceptable distance of a magnetic sensor 18 positioned on a stationary member 20 of the exercise machine 12. The sensor 18 has means 28 having a power supply 34 for detecting the magnetic field 26 and displaying the repetition number on a visual display means 22. A reset button 30 is provided along with an alternative embodiment providing a timed reset 38. Also, an embodiment is described wherein a voice synthesizer 42 announces the number of the repetition in addition to having a display 22.