Physical Growth

Height and Weight in Infancy (Birth - One Year)

Babies, like adults, vary in size and shape. Although babies can vary a lot in their growth and still be healthy, watching growth is a way for you to see if they are getting good nutrition (enough to eat) and have adequate sustenance to support the processes of development.

The following heights and weights are general guides (averages):

  • The average weight at birth varies from 6 to 9 pounds.
  • The average length at birth varies from 18 to 22 inches.
  • Babies gain 4 ‑ 5 ounces a week (11/2 pounds a month) from birth to 6 months, doubling their birth weight by 5 months (for example: 7 pounds at birth = 14 pounds at 5 months).
  • They gain 3 ‑ 4 ounces a week from 6 months to 1 year, tripling their birth weight by 1 year (7 pounds at birth = 21 pounds at 1 year).
  • By their first birthday, babies have increased their birth length by half of their birth length. A baby 20 inches at birth will be about 30 inches at 1 year.

Height and Weight (Birth to Preshcool Years)

Growth slows down by the end of the first year. Preschool years are a time of slow but steady growth for children. During their second year (from age 1 ‑ 2), children gain about 5 ‑ 6 pounds. From 2 to 5 years, they gain about 4 ‑ 5 pounds a year. Generally children’s height at 2 years will be half of their adult height. (See the growth chart below.)


BIRTH 7 pounds Birth 20 inches
5 MONTHS Double birth weight    
1 YEAR Triple birth weight 1 YEAR And half of birth height
2 YEARS Gain 5-6 pounds/year 2 YEARS Half of adult height
2-5 YEARS Gain 4-5 pounds/year    


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