Teens are still growing. The CDC interprets BMI between ages 2 and 19 as a percentile against same-age, same-sex peers. Underweight is below the 5th percentile, healthy weight 5th to less than 85th, overweight 85th to less than 95th, and obesity 95th and above. Around age 20, the adult WHO cut-offs take over.
Puberty, growth spurts and body composition
Puberty causes rapid changes in body composition that BMI can obscure. A 14-year-old boy in a growth spurt can temporarily cross the overweight band and then settle back into the healthy range as height catches up with weight. A single reading in the overweight or obese band does not by itself indicate a problem — the trend over time matters more than the snapshot. Plot your height and weight against the CDC growth charts for a clearer picture.
What this calculator does
The teen calculator uses the same form as the standard BMI calculator, but the result is labelled against the CDC reference bands rather than the adult WHO cut-offs. It also reports BMI Prime and Ponderal Index for completeness, and shows the healthy weight range, ideal weight (Devine) and lean body mass (Boer) — useful as background, not targets. Body fat percentage is suppressed because the Deurenberg formula was derived on adults.
Next steps
- Child BMI calculator for ages 2–12
- Kids BMI calculator
- Adult BMI calculator for age 20+
- CDC growth charts