Next you must obtain the circumference of your belt. Circumference is measured in inches. Two ways to measure the belt. First, pinch both ends and lay flat on a ruler. Measure the pinched belt and multiply that measurement by two.
Second method is cut the old belt and lay on ruler.
The length is your circumference. If you like, you may also order by diameter, which are measured in millimeters. Take the circumference, measured in inches and multiply by 25.4 mm.