If doing yardage, the minimum you need is 2.5 yards. (5 wof cuts of 18 inches each) take the selvedges off each wof then 1/4 the length. (it will give you nearly 11 inches) the caveat to that is if your fabric has those insane deep selvedges. The rest depends on your vision for your finished quilt, borders, sashing, extra blocks etc....