Add all the sides of your quilt together (its perimeter), add 15-18” to that number (for miters, seams and overlap), divide the total by 40 (WOF after washing) and round up to the next whole number. That’s how many strips you will need to cut. Multiply that by the width of the cut binding strip you want and divide that number by 36 (inches in a yard). That will give you the yardage (as a decimal) you need for your binding.
So as a formula, I’d say something like this: (((QP+18 )/40)xCBW)/36=BY where QP=quilt perimeter. CBW=cut binding width, and BY=binding yardage :lol: