You will have to measure the finished block, + width of bands you put between the blocks, + any edging. Draw it out on graph paper to get a view of the pattern squares needed for your size.
[ EDGING, BAND, SQUARE, BAND,SQUARE, BAND, SQUARE, BAND, SQUARE, BAND, EDGING]
1" 4.5" 17.5" 4.5" 17.5" 4.5" 17.5" 4.5" 17.5" 4.5" 1" = 94.5"
* .5 for quarter inch seams