Originally Posted by
gingerd
I guess I don't understand why they wouldn't also tell me how much backing fabric that I need for the quilt.
Because there are way too many variables. As previously stated, the author wouldn't know if you were piecing it or using a wide back, or if you were going to hand quilt it, or send it to a longarmer, and every longarmer has her preference of how much fabric you need depending on how she has her longarm set up. Also, a lot of people do not make the exact same size quilt as what the pattern states.
As you gain experience, you will be able to determine for yourself how much fabric you will need.