AWilson...they are called 12" blocks but you will find that they are actually 12 1/2"when you sew them together and mail them. That way it gives the receiver a 1/4" on allsides to sew the blocks to the sashing or other blocks, thus making it a real 12" block. Hope this makes sense. The blocks in Quilterscache are 12" finished but actually when YOU make them they will be 12 1/2". I think everyone has made one too small or too big but its easy to take care of if that happens.. Noone of us is perfect and its just to have FUN and share friendships. I think you will have a blast with us!