Newborns often lose around 8 oz (226.8 g) in the first 4 to 5 days after birth but regain it by about 10 to 12 days of age. In the first month, the typical newborn gains about 0.7 oz (20 g) a day, or about 4 oz (110 g) to 8 oz (226.8 g) a week. The average length of full-term babies at birth is 20 in. (50 cm), although the normal range is 18 in. (45.7 cm) to 22 in. (60 cm). In the first month, babies typically grow 1.5 in.