1. What is BMI?

Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adults and children. 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 adjusted for children:

Where:

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

For children: The result is compared against age- and sex-specific percentiles from CDC growth charts.

3. Importance of BMI for Children

Details: BMI-for-age is the recommended measure for screening overweight and obesity in children aged 2-19 years. It helps identify potential weight problems that may lead to health issues.

4. Using the Calculator

Tips: Enter weight in kilograms, height in centimeters, and age in years (2-19). For accurate results, measure height without shoes and weight with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: Why is child BMI different from adult BMI?
A: Children's body composition varies by age and sex, so BMI must be interpreted relative to other children of the same age and sex.

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

Q3: When should I be concerned about my child's BMI?
A: Consult a doctor if BMI is below 5th percentile or above 85th percentile, or if there are sudden changes.

Q4: Are there limitations to BMI for children?
A: BMI doesn't distinguish between muscle and fat, and may not accurately reflect body fat in very muscular children.

Q5: How often should children's BMI be checked?
A: Annual BMI screening is recommended for children aged 2-19 years.