Measuring belts for sewing machines.

Measuring belts for sewing machines is not rocket science,but there is a right way, and a wrong way,manufactures seem to have another way of measuring belts,which makes the process incorrect when ordering belts.
I actually ordered a 14 1/4" belt I need, and the belt I got was way to short,many times I bought belts from different suppliers with the same results,I finally found a supplier that would work with me,and was sold a 15" belt when in fact the belt supplied was only 14 1/2" circumference around the inner side of the belt,the supplier was told the belt was 15",this is the manufactures fault.

[@richyearle007]

Colin,going on your measurement there is only 1/16th difference between the inside and outside circumference of the belt. Just saying.