BMI Calculator for Kids
Calculate BMI for children and teens and understand how results are interpreted using age- and sex-specific percentile charts.
Understanding BMI for Children and Teens
While the formula to calculate Body Mass Index (BMI) is the same for children as it is for adults, the interpretation is very different. For individuals aged 2 to 19, BMI is not viewed as a single number with fixed categories like 'underweight' or 'overweight'. Instead, it is plotted on age- and sex-specific percentile charts developed by organizations like the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC).
Why is BMI for Kids Different?
Children and teenagers are constantly growing. Their body composition (the amount of fat and muscle) changes significantly with age and differs between boys and girls. A healthy BMI for a 6-year-old is very different from a healthy BMI for a 16-year-old. Because of this, a fixed scale doesn't work.
BMI-for-age percentile charts account for these differences. When a child's BMI is calculated, it's compared to the BMIs of other children of the same age and sex.
📊 Interpreting BMI Percentiles
This calculator provides the BMI value. A healthcare provider would then use that value to determine a percentile, which generally falls into these categories based on CDC/WHO guidelines:
| Weight Status Category | Percentile Range |
|---|---|
| Underweight | Less than the 5th percentile |
| Healthy weight | 5th percentile to less than the 85th percentile |
| Overweight | 85th to less than the 95th percentile |
| Obesity | Equal to or greater than the 95th percentile |
This calculator does not assign a weight status category for children and teens. It provides the BMI number so you can discuss it with a healthcare professional, who can plot it on the appropriate growth chart.
Frequently Asked Questions (FAQ)
- Is this calculator a diagnostic tool?
- No. This calculator is a screening tool. It provides a BMI number, but only a qualified healthcare provider can interpret this number in the context of your child's overall health, growth patterns, and other factors to determine if their weight is healthy.
- What should I do if I am concerned about my child's BMI?
- If you have any concerns about your child's weight or growth, it is essential to speak with a pediatrician or family doctor. They can perform a comprehensive evaluation and provide guidance on nutrition and physical activity.
Disclaimer: This tool is for informational purposes only and is not a substitute for professional medical advice.