1. What is BMI-for-age?

BMI-for-age is a measure that takes into account a child's age and sex when assessing their weight status. For children, BMI is age- and sex-specific and is often referred to as BMI-for-age. It's the most common indicator used to screen for weight categories that may lead to health problems.

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 a percentile ranking. This calculator provides the raw BMI value which should then be interpreted using appropriate growth charts.

3. Importance of BMI Calculation for Children

Details: BMI-for-age is the recommended measure for screening overweight and obesity in children and teens. It's a reliable indicator of body fatness for most children and teens, even though it doesn't measure body fat directly.

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 is BMI interpreted differently for children than adults?
A: Children's body composition varies as they grow, and differs between boys and girls. BMI-for-age accounts for these differences.

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

Q3: How often should children's BMI be checked?
A: The AAP recommends BMI screening at least annually for all children and adolescents.

Q4: Are there limitations to BMI-for-age?
A: BMI is a screening tool, not a diagnostic measure. It doesn't distinguish between fat and muscle mass or assess body fat distribution.

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