All this measuring, cutting, squaring-up is foreign to me . I have bought so many rulers from all companies. My last purchase was from Nancy's Notions for "The Block Maker" which squares up blocks from 6" to 16". It was rather expensive. I have 3 different 12.5 " square rulers because I didn't know which one was better! I have square rules from 2.5" up to the 16" and many regular straight rulers. I am learning and finding out what works best for me and am not going to buy any more rulers. I have really only made 11 blocks in the past year since I began this new "Quest" of Quilting!! I learn something new everyday!