if the quilt size is about 38 x 44 you will to add at least 2 to 4 inches to each side, to keep from haveing to work my brain LOL, I add 10 inches (the extra goes in my stash)
48 X 54 inchs plus of minus is what I would look for on the package or 1 1/2 yards off the roll.
I add that much as I load it on my HQ midarm.
hope that helps