http://www.quilterscache.com/StartQu...iltingtwo.html
Hear is a website for size charts
I would figure out what size borders and how many you want first
and then take the rest of the dimensions and go from there
Example
88x96 let just make it 88x98 for more even math
Say you allow 18 inches for border all around that would be 9 inches on each side leaving you with
70 x 80 for the top divide each of those by 5 means you would have 14 squares across by 16 squares down multiply the 2 means you would need 224 squares
1 yard is 36 by 44 so you can get 7 squares across and 8 down multiple the 2 you can get 56 squares from a yard
Hope this helps