You usually know instinctively if your baby is healthy, but comparing her growth to "normal" guidelines is a good way to help put your mind at ease. Many babies grow a half inch to an inch per month between birth and six months. In that same period, babies can gain five to seven ounces per week. Between six months and a year, she'll probably grow about three-eighths inch per month and gain three to five ounces per week. It's normal for her to double her birth height and triple her birth weight by her first birthday.

Source:
"Question: Infant growth: What's normal?," http://www.mayoclinic.com/health/infant-growth/AN01654