average weight gain for toddlers
Birth. The average newborn is 19.5 inches long and weighs 7.25 pounds. Boys have a head circumference of about 13.5 inches and girls measure in at 13.3 inches, according to the National Center for Health Statistics.1  Baby Growth Charts: Calculate Height and Weight.2  Charting Baby's Development.irth. The average newborn is 19.5 inches long and weighs 7.25 pounds. Boys have a head circumference of about 13.5 inches and girls measure in at 13.3 inches, according to the National Center for Health Statistics.