The average weight of males and females at 13 years of age is 100 and 101 pounds, respectively, according to Disabled World health experts. The weight of young adults this age ultimately depends on the height, gender and bone composition of the individual.
Many young teens undergo growth spurts resulting in rapid weight gain and body changes; girls are particularly prone to significant changes, since they typically mature earlier than teenage boys.
Desired weight should be calculated in conjunction with a body mass index (BMI) calculator, which measures the estimated amount of body fat present based on height and weight, according to the National Heart, Lung and Blood Institute. Individuals with a BMI of 18.5 are considered underweight; those up to 24.9 are considered to be of ideal weight. Measurements of 25 or greater signify an individual to be overweight, while those 30 or greater indicate obesity.