Child BMI Calculator & Key Facts
Child BMI Calculator
For children and teens (ages 2 through 19)
About This Child BMI Calculator
This tool estimates weight status for kids and teens in United States based on age, sex, height, and weight. It calculates a ratio by dividing weight in kilograms by height in meters squared, then compares results to standardized percentile charts. Percentiles indicate categories such as underweight, healthy weight, overweight, or obese.
For ages 2 through 19, percentile ranges vary between boys and girls due to natural growth differences. A value below 5th percentile usually suggests underweight, 5th to 84th percentile indicates healthy weight, 85th to 94th percentile signals overweight, and 95th percentile or higher shows obesity.
To use, input age in years and months, sex, height in inches or centimeters, and weight in pounds or kilograms. Some tools automatically convert units for accurate comparison with national growth charts. Results appear immediately, showing percentile and corresponding category, making it easy for caregivers or educators to track trends over time.
Regular monitoring is recommended, as ratios can change rapidly during growth spurts. While this measure alone does not provide medical diagnosis, it serves as a guideline for evaluating trends relative to peers. This chart-based method is commonly used in pediatric offices, schools, and community programs across United States.
