You're just going to have to do the math on this one. Figure out the cut sizes of each piece and how many of those cuts you need for an entire quilt, which will depend on the number of blocks you have graphed out on graph paper. Then you can determine how much fabric is required to give you that many cuts. You'll have to do this for each fabric you intend on using. You could also go buy a fabric calculator and it will do the math for you, but you still have to insert the numbers, so you still have that to figure all that stuff out.