I tend to make them about 45x45 since dr.s advise that we don't use blankets on baby, in the crib, til I think a yr. by then the 45x45 size gives em good coverage and can be used on the floor, over a car seat and to wrap em up even when they are under a yr. I've made em smaller for moms who need one in a bassinet while they are at grandma's or in the pack n play at the sitters. unless you are using a pattern I think size can vary with no problems! I like the fabrics you chose.