Last one I did was about 38 by 40. just did have enough backing with so I didn't have to piece it. If it were me, I wouldn't want a baby quilt that wasn't almost square. I think of a baby quilt is one you lay the baby on in the middle, bring one corner up and then the two side over top wrap then up in it. You have the top corner to bring down over the head when going outdoors. Could do that very easily if it was rectangular.