1. What is BMI?

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, overweight and obesity in adults and adolescents. For adolescents, BMI is age- and gender-specific and compared to percentiles.

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 adolescents, the calculated BMI should be compared to age- and gender-specific percentiles for proper interpretation.

3. Importance of BMI Calculation

Details: BMI is an inexpensive and easy screening method for weight category—underweight, healthy weight, overweight, and obesity. For adolescents, tracking BMI over time can help identify potential weight problems.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, age in years (2-20), and select gender. All values must be valid (weight > 0, height > 0, age between 2-20).

5. Frequently Asked Questions (FAQ)

Q1: What is a healthy BMI for adolescents?
A: Healthy BMI varies by age and gender. Typically between the 5th and 85th percentiles on CDC growth charts.

Q2: Why use age and gender for adolescent BMI?
A: Body composition varies with age and between genders during puberty, so percentiles account for these normal variations.

Q3: How often should BMI be calculated for adolescents?
A: The American Academy of Pediatrics recommends BMI screening annually for all children and adolescents.

Q4: Are there limitations to BMI?
A: BMI doesn't directly measure body fat and may misclassify muscular individuals. It's a screening tool, not a diagnostic.

Q5: Where can I find BMI percentile charts?
A: The CDC provides growth charts with BMI percentiles by age and gender on their website.