1. What is BMI?

Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

For children and teens, the BMI number is plotted on the CDC BMI-for-age growth charts to determine a percentile ranking.

3. Importance of BMI Calculation for Children

Details: BMI-for-age is the recommended indicator for screening overweight and obesity in children and teens. It accounts for normal differences in body fat between boys and girls and differences in body fat at various ages.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and age in years (2-19 years). For accurate results, measurements should be taken with minimal clothing and no shoes.

5. Frequently Asked Questions (FAQ)

Q1: Why is BMI interpreted differently for children than adults?
A: Children's body composition varies as they grow, and between boys and girls. BMI-for-age compares a child's BMI with other children of the same age and sex.

Q2: What do the BMI percentiles mean?
A: Underweight (<5th percentile), Healthy weight (5th to <85th percentile), Overweight (85th to <95th percentile), Obese (≥95th percentile).

Q3: How often should children's BMI be calculated?
A: The American Academy of Pediatrics recommends BMI calculation at least annually as part of routine health supervision.

Q4: Are there limitations to BMI for children?
A: BMI doesn't directly measure body fat and may be misleading for very muscular children or those with certain medical conditions.

Q5: Where can I find CDC growth charts?
A: CDC growth charts are available at https://www.cdc.gov/growthcharts/.