A normal full-term baby weighs about 2.5-4kg at birth. In the first 3 months, the baby gains about 180-200g per week, 150-180g per week from 4-6 months, 90-120g per week from 6-9 months, and 60-90g per week from 9-12 months. by weight gain multiplier, the baby weighs twice as much at birth at 6 months, about 3 times as much at 1 year, about 4 times as much at 2 years, and about 4.6 times as much at 3 years. In the second year of life, babies grow on average 2.5-3 kg, and after the age of two, they grow on average about 2 kg per year until puberty. The development of boys and girls is different, parents can refer to the above baby height and weight data to see if the baby’s length and weight are normal.