I have not had good luck using pre-cuts and find that cutting my hsts down from a larger block work out the best. I will also add that it is just not the pre-cut squares that can be off. The jelly rolls are notorious. It's unfortunate because the reason so many of us buy the pre-cuts is to save time and fabric waste. So, if you have a pattern that is forgiving, pre-cuts are great...otherwise reconsider, avoid frustration and buy fabric off the bolt.