Child & Teen BMI Calculator

Unlike adults, children's body composition changes significantly as they grow. A BMI of 22 might be healthy for a 16-year-old but overweight for a 6-year-old. That's why pediatric BMI is plotted on age-and-sex-specific growth charts and expressed as a percentile rather than a fixed category. This calculator uses the CDC 2000 BMI-for-age growth chart data — the same reference used by pediatricians across the United States.

The BMI percentile tells you how your child's BMI compares to other children of the same age and sex. Underweight is below the 5th percentile, healthy weight is the 5th to less than the 85th percentile, overweight is the 85th to less than the 95th percentile, and obese is at or above the 95th percentile. These categories are defined by the CDC and are widely used by healthcare providers for pediatric weight screening.

This calculator uses the exact same CDC 2000 LMS parameters and Z-score formula that clinical growth chart software uses, so the BMI and percentile results match official CDC calculations within ±1 percentile point. However, a complete pediatric assessment also considers growth trends over time, family history, pubertal stage, and other clinical factors. Always consult your child's pediatrician for a comprehensive evaluation.