You can also cut 2 squares..layer right sides together and sew 1/4" around all four sides. Then slice diagonally across the middle and then slice again diagonally to remaining 2 corners. This gives you 4 completed HST's. Very fast and accurate. I did this for the first time on my most recent project and will probably do that each time. If you need your HST's to finish at a certain size, I am not sure how to determine the size of the squares but that information is probably available (somewhere!)