Refer to your Proform elliptical owner's manual to determine the stride length of the machine. If the manual provides the stride length in inches, convert into feet by dividing by 12. Skip to Step 4.
Measure the wheel from edge to edge across the center to determine the diameter of the wheel in inches if you do not know the stride length. Multiply the diameter by 3.14 to calculate the circumference, or perimeter, of the wheel in inches. Divide the circumference in inches by 12 to convert the measurement to feet.
Divide 5,280 (the number of feet in a mile) by either the stride length or circumference of the wheel in feet. The result indicates the distance you travel with each revolution of the wheel.
At the end of your workout, multiply the total revolutions you see on the Proform elliptical's display by the stride length or wheel circumference to calculate the total miles you traveled during your workout.