BMI for Children Calculator

Calculate BMI for children and teens and see percentile.

Health

A Better Health Metric for Growing Kids

BMI in children and teens (ages 2-20) is interpreted differently than in adults. Because children are constantly growing, their BMI is plotted on age- and sex-specific percentile charts from the Centers for Disease Control and Prevention (CDC). This calculator computes the BMI and then tells you which percentile your child falls into, providing a more accurate assessment of their weight status relative to their peers.

The Formulas Explained

  1. BMI Calculation: The standard BMI formula is used first.
    • BMI = weight(kg) / [height(m)]²
  2. Percentile Ranking: The calculated BMI is then compared against the official CDC growth charts to find its percentile.
    • Underweight: Less than the 5th percentile.
    • Healthy weight: 5th to less than the 85th percentile.
    • Overweight: 85th to less than the 95th percentile.
    • Obese: Equal to or greater than the 95th percentile.

How to Use the Calculator

  1. Enter Details: Input your child's age (between 2 and 20), gender, height, and weight.
  2. Select Units: Choose between Metric and Imperial units.
  3. Calculate: The tool will display the child's BMI and their corresponding percentile category.

Real-World Example

A 10-year-old boy is 56 inches tall (142 cm) and weighs 75 pounds (34 kg).

  • His calculated BMI is approximately 16.8.
  • When compared to the CDC growth chart for 10-year-old boys, a BMI of 16.8 falls around the 75th percentile, which is in the Healthy Weight range.

Frequently Asked Questions (FAQ)

  • Why can't I use the regular BMI calculator for my child? A specific BMI value means different things at different ages. A BMI of 22 might be healthy for a 15-year-old but could be classified as overweight for a 7-year-old. The percentile shows how your child's BMI compares to others of the same age and sex.
  • What should I do if my child is in the overweight or obese category? If you have concerns about your child's weight, it's very important to speak with a pediatrician or family doctor. They can provide a comprehensive assessment and guidance on healthy eating and activity habits for growing children.
  • Is this calculator a substitute for medical advice? No. This tool is for informational purposes only and should not replace a consultation with a qualified healthcare professional.