Adolescents grow in spurts which start as their bodies respond to growth and sex hormones. Boys and girls begin and experience these spurts at different times and individual bodies experience them differently. Statements about averages at any age during adolescence are full of variables. Although they are close to physical adulthood, 16-year-olds have a wide range of average heights and weights.
Girls' growth hormones kick into high gear around 9 years of age, but varies from individual to individual. Growth and sex hormone-initiated growth spurts peak at an average age of 11.5 and last for two to three years. By 16 years of age, many girls have attained their adult heights. Girls in the fiftieth percentile at age 9 weigh about 64 lbs and stand 52 inches tall; at age 12, they weigh about 85 lbs and stand 5 feet tall. Sixteen-year-olds in the fiftieth percentile stand 5 feet, 4 inches tall and weigh 115 lbs as their growth curves level off.
Boys begin growth spurts around 11 years of age and are growing fastest at around 13.5 years old. Because boys start growing later than girls, their growth plates, the soft colloidal tissue between bones, hardens into cartilage later, making adult men end up taller than adult women on average. The majority of 16-year-olds are past the peak of their growth spurt but many are still growing. Boys in the fiftieth percentile at age 11 weigh about 73 lbs and stand 61 inches tall; at age 14, they weigh about 110 lbs and stand 5 feet, 5 inches tall. Sixteen-year-olds in the fiftieth percentile stand 5 feet, 7 inches tall and weigh 132 lbs as their growth curves level off.
The CDC publishes average height and weight for children and adolescents and periodically updates figures. The 2000 figures were developed using figures from the National Center for Health Statistics and National Center for Chronic Disease Prevention and Health Promotion. All averages are approximate due to individual differences. Because height and weight vary, the CDC recommends using actual height and weight to determine body mass. (BMI) The BMI number gives a value to use in determining relative underweight, overweight and obesity.
Average weights for 16-year-old girls range from 95 lbs at the third percentile to 185 lbs at the ninety-seventh percentile. Average heights range from 5 feet to 5 feet, 9 inches. Girls' BMI numbers range between an underweight 17.75 to overweight 28.75; the BMI at the fiftieth percentile is 20.5. Average weights for 16-year-old boys range from 103 lbs to 195 lbs and heights range from 5 feet, 3 inches to 6 feet, 2 inches. Underweight BMI average is 17 and the overweight BMI average is 27.25. Boys average a 20.5 BMI at the fiftieth percentile.