Some of the most common child development questions parents have revolve around whether their son or daughter is growing properly. Has he gained enough weight? Is she too small for her age? Is he or she too chunky? How tall will they be when fully grown?
While remembering that each child is their own unique human being, and “normal” is always a relative term wherein children are concerned, here are some guidelines outlining typical growth and physical development in children:
Rate of children’s growth
During their first year of life children are growing by leaps and bounds. Between week 1 and around 3 months of age, babies will gain around an ounce per day, or roughly half a pound per week. From 3 to 6 months this slows to around half-a-pound in added weight every 2 weeks. By 4 to 6 months in age, most babies will have doubled their birth weight. Growth then slows down after 6 months, but babies will continue to add around a pound per month up until their first birthday.
Growth continues too slow during the second year of a child’s life. Children gain an average of only around 5-6 pounds (2.5 kg) over the entire year. Children start to grow leaner and more muscular, losing some of their baby fat.
Height-wise, children grow an average of 5 inches (1.2 cm) during their second year. By the time kids turn two, most children will be around 32 to 36 inches in height (81-91 cm), and will weigh approximately 4-times their birth weight; so around 24 to 35 pounds on average.
During the preschool years kids continue to thin out and take on a more muscular, adult-like shape. Some kids will have completely lost their baby fat by age 3 or 4, whereas others will still have a chubby look about them. “The average child becomes thinner and stronger each year as he or she grows taller,” notes professor Ken Van De Graaff. “The average 10-year-old, for example, can throw a ball twice as far as the average 6-year-old.” (De Graaff, 2000)
Preschoolers continue to grow at a more modest pace, with periodic growth spurts between the ages of 3 and 6. By the age of 6, the average child weighs around 48 pounds and is 46 inches tall. (Watson & Lowrey, 1967)
After toddlerhood, the “childhood years are a period of relative steady growth until preadolescence, which is characterized by a growth spurt. The average weight gain during childhood is about 3 to 3.5 kg (7 pounds) per year. There is an average increase in height of 6 cm (2.5 inches) per year.” (De Graaff, 2000, p. 757)
The adolescent growth spurt
The adolescent growth spurt can begin as early as age 8 for girls and age 10 for boys. Girls start their growth spurt nearly 2 years sooner on average and reach a mature height much earlier. Between the ages of 8 1/2 and 13 1/2, American girls grow around 11 inches. Between ages 10 1/2 and 16 1/2, American boys grow around 12-13 inches. (McGinty, 2019)