Normal growth is one of the best indicators of good health and nutrition. Normal heights and weights, however, are difficult to define. Short parents tend to have short children. Tall parents tend to have tall children. For any given height, an ideal weight can be determined from a growth chart. An infant with failure to thrive is underweight for his height. An obese child is overweight for his height.
Your healthcare provider will weigh and measure your child on each well child visit and plot these numbers on a standard growth chart. Your child's growth rate over time reveals the most about his or her nutritional health.
The following facts and figures may answer some of your questions about normal growth.
Weight: 7 pounds, 5 ounces (normal range: 6 to 10 pounds)
Length: 20 inches (50 cm) (normal range: 18 1/2 to 21 1/2 inches)
Head circumference: 13.8 inches (35 cm) (normal range: 33 to 37 cm)
A premature baby is born before 37 weeks gestation and usually weighs less than 5 and 1/2 pounds (2.5 kilograms).
5 months: double birth weight
14 months: triple birth weight
3 years: quadruple birth weight
1 to 6 years: weight in pounds = (age x 5) + 17
7 to 12 years: weight in pounds = (age x 7) + 5
4 years: double birth length
13 years: triple birth length
2 to 14 years: height in inches = (age x 2 1/2) + 30
(1 foot = 12 inches; 1 inch = 2.5 centimeters)
The adult height cannot be predicted, except with a growth chart. If a child has consistently followed one height line or curve (such as the 30th percentile), he or she probably will end up in the 20th percentile as an adult. The only formula that can give an approximate adult height is based upon the mid-parent height. But there is still tremendous variation.
The mid-parent height is the sum of the parents' heights divided by 2. With that number you can estimate your son or daughter's height using the formulas below.
Mid-parent height plus 2 1/2 inches = Adult height (boys)
Mid-parent height plus 2 1/2 inches = Adult height (girls)