If you are 17 weeks pregnant how big is the baby?

I am currently 15 weeks pregnant and I've gotten estimates for baby size at 17 weeks anywhere from 3.5 oz. to 9 oz. It really depends on the baby and the mother and the pregnancy itself. The baby at this point it rapidly growing and will double in size from 15 weeks to 17 weeks, so the range that is considered "normal" is rather large.