Originally Posted by
momsobon
length x width gives you around the quilt then you divide by 42 that gives you the strips and say you need 8 you x that by 2.5.....so that will give you the amount you need so you don't over by so much but we always need something in the stash.
Oops! You forgot about the other two sides of the quilt. And it is added, not multiplied. You need to take length + width and double that. You have to add some for all the seams in the binding, and another width-of-binding for the overlap at the end. Each strip gets width-of-binding taken off of it for seaming.