1. What is BMI for Children and Teens?

BMI-for-age is a screening tool for underweight, healthy weight, overweight, and obesity in children and teens aged 2-19 years. Unlike adults, BMI in children is age- and sex-specific because their body composition varies as they grow.

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 children and teens, the BMI number is plotted on CDC growth charts to determine the BMI-for-age percentile.

3. Importance of BMI Calculation

Details: BMI-for-age is the recommended screening measure because it takes into account normal variations in body fat at different ages and between boys and girls.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: How is BMI interpreted for children?
A: BMI is plotted on sex-specific CDC growth charts to determine the percentile, which indicates relative position compared to peers.

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

Q3: Why use BMI instead of other measures?
A: BMI is a simple, non-invasive screening tool that correlates well with body fatness for most children and teens.

Q4: Are there limitations to BMI?
A: BMI doesn't directly measure body fat and may misclassify muscular teens as overweight or fail to identify those with excess body fat.

Q5: What should I do with the BMI result?
A: Consult a healthcare provider for interpretation and potential next steps based on the BMI percentile.