I have a new Ap for my iPad called "Block Fab" by Mary Podlecki. It has 50 different blocks and will calculate yardarge needed and cuts for you, for the block and the whole quilt. It will let you "combine" blocks - for example a small Carpenters Frame inside a large Carpenters Frame, or pair two blocks like Crossing Ohio with a 7 Grid Chain. It can even display in a few different colorways for ideas.
and ... it was FREE.
I'm happy :)