I use QuiltCalc on my iPhone. It is by Robert Kaufman fabrics and helps you determine 1) fabric measurement, 2) backing and batting, 3) piece count, 4) pieces to yardage area, 5) binding, 6) border yardage, 7) square-in-a-square, and 8) set-in and corner triangles. I'm glad you asked the question and I'm anxious to see what else is out there.