I think it depends on the block.....and how far out of square it is. Mine - when there are bias edges, is rarely more than about 1/8 inch and a bit off...that will easily get eased in during assembly. Any time i've had a bigger discrepancy, i've gone back and looked at my seams - usually i've goofed up there. I've also noticed that pressing seams flat vs to one side causes a difference in the size of the block....flat seam pressing blocks are bigger.....or is should say, mine are.