Very seldom do I ever cut material for binding.. My backing is always bigger than my quilts... I trim the backing so that it is 1 1/2 inch larger than the quilt on my kings and queens.. I fold it once and then over again.. I then whip stitch it to the front to secure it... Sometimes I do machine stitch it... On smaller projects I adjust how much material to leave..
I like this method because it makes for a beautiful finished binding look on the top of the quilt.. Also saves money and time...