1. What is BMI for Teens?

BMI-for-age is the measure used to assess weight status in children and teens aged 2-19 years. Unlike adults, BMI values for children and teens are age- and sex-specific because their body composition varies as they age and between boys and girls.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

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

Explanation: The result is then compared to CDC growth charts to determine the weight status category based on age and sex.

3. Importance of BMI Calculation

Details: BMI screening for children and teens can identify possible weight problems, but it's not a diagnostic tool. Healthcare providers need to perform further assessments to determine if excess fat is a problem.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, age between 2-19 years, and select gender. All values must be valid (weight > 0, height > 0, age 2-19).

5. Frequently Asked Questions (FAQ)

Q1: Why use age- and sex-specific BMI for teens?
A: Because body composition varies by age and between boys and girls as they grow and develop.

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

Q3: How often should BMI be checked in teens?
A: The AAP recommends annual BMI screening for all children and teens aged 2 years and older.

Q4: Are there limitations to BMI for teens?
A: BMI doesn't distinguish between fat and muscle, so athletic teens may have high BMI without excess fat.

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