1. What is BMI for Children?

BMI for children and teens is calculated the same way as for adults, but the results are interpreted differently. For children, 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:

Where:

• \( weight \) — Body weight in kilograms
• \( height \) — Height in meters

Note: For children, the BMI number is plotted on the CDC BMI-for-age growth charts to determine the corresponding percentile.

3. Importance of BMI Percentile

Details: BMI percentiles are the most commonly used indicator to assess the size and growth patterns of children in the United States. The percentile indicates the relative position of the child's BMI among children of the same sex and age.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, age in years (2-19), and select gender. All values must be valid (weight > 0, height > 0, age between 2-19).

5. Frequently Asked Questions (FAQ)

Q1: Why use BMI-for-age for children?
A: Because children's body composition varies as they grow, and BMI changes with age. BMI-for-age accounts for these normal growth patterns.

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

Q3: How often should children's BMI be checked?
A: The AAP recommends BMI screening annually starting at age 2.

Q4: Are there limitations to BMI for children?
A: BMI doesn't distinguish between fat and muscle mass. Athletic children may have high BMI due to muscle rather than fat.

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