1. What is BMI for Children?

Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to children and teens. 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 adjusted for boys using WHO growth charts:

Where:

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

Explanation: The result is compared against WHO growth standards for boys to determine the percentile.

3. Importance of BMI Calculation

Details: BMI-for-age is the recommended indicator for screening overweight and obesity in children aged 2-20 years. It helps identify potential weight problems that may lead to health issues.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and age in years (2-20). For accurate results, measure height without shoes and weight with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: Why use BMI-for-age instead of regular BMI?
A: Children's body composition varies with age and sex, so BMI must be interpreted relative to other children of the same age and sex.

Q2: What are the BMI categories for children?
A: Underweight (<5th percentile), Healthy weight (5th-85th), Overweight (85th-95th), Obese (≥95th percentile).

Q3: How often should my child's BMI be checked?
A: Annual BMI screening is recommended for children aged 2 years and older.

Q4: Are there limitations to BMI for children?
A: BMI doesn't distinguish between fat and muscle mass. Athletic children may have high BMI without excess fat.

Q5: Where can I find official WHO growth charts?
A: WHO growth standards are available on the World Health Organization website.