How much should a 12-year-old weigh?

According to the Centers for Disease Control and Prevention, a 12-year-old child has a healthy weight if his body mass index for his age group ranges between the fifth and 85th percentile. A child's birth date, height, weight, date of the measurement and sex can be used to determine BMI.

Because healthy weight changes as height increases, and body fat ratios change as a person gets older, the CDC does not provide a range of healthy weights for any age. Even though it recommends seeing a physician to accurately determine a child's body mass index, it also provides helpful tutorials to assist parents in calculating their child's body mass index with precision.