1. What is BMI?

Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to teenage girls. For teens, BMI is age- and sex-specific and is often referred to as BMI-for-age.

2. How is BMI Calculated?

The calculator uses the standard BMI formula:

Where:

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

Note: For teenage girls, the BMI number is then plotted on CDC growth charts to obtain a percentile ranking.

3. BMI Categories for Teenage Girls

Categories:

• Underweight: BMI < 18.5
• Normal weight: BMI 18.5-24.9
• Overweight: BMI 25-29.9
• Obese: BMI ≥ 30

Note: These are general categories. For precise assessment, consult growth charts specific to teenage girls.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and age between 13-19 years. All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why is BMI different for teenage girls?
A: BMI interpretation accounts for normal variations in body composition during puberty and differences between sexes.

Q2: How accurate is BMI for teens?
A: BMI is a screening tool but doesn't directly measure body fat. Athletes with high muscle mass may have higher BMI without excess fat.

Q3: What's a healthy BMI for a 15-year-old girl?
A: Typically between 18.5-24.9, but exact healthy range depends on growth charts and individual factors.

Q4: When should I be concerned about my teen's BMI?
A: If BMI is below 18.5 or above 25, or if there are sudden changes, consult a healthcare provider.

Q5: Can this calculator be used for adult women?
A: The calculation is the same, but interpretation differs. Adult categories don't account for age like teen BMI percentiles do.