Happylab: I agree with Judy. Because I make a square quilt I would use 64 blocks. Depending on the pattern and whether you want borders you might want to reduce that number accordingly. Its kind of hard to plan ahead with a mystery, which is why I frequently make less than I really think I will need, so I can add borders if I want. Just a comment, and not really relevant to anything, but I make the 96X96 for a double or queen size bed. I like the fall to be longer then I don't need a dust ruffle. The last king I made measure 118 X 118, a monster.