I have to calculate fabric a lot and usually I am always a bit short doing charity quilts from donated fabrics. I have no idea what the Belle Fluer block looks like. I have Electric Quilt 5 and that is accurate except it assumes that long pieces are not cut from selvage to selvage. But it gives me a ball point reference. If the pattern has yardage for # of blocks for a lap, how many more blocks will you need to achieve your queen size. Times 3?? Most times with patterns, I need to reduce them so I just have my calculator and count how many 2.5 squares I can get out a jelly roll strip and divided that by how many 2.5" squares I need for the quilt. That division will tell me how many jelly strips I need. You can also look in various queen size pattern similar and be able to guess how much you need. Good Luck !!