1. What is BMI?

Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age. It's a screening tool that may indicate whether a child is underweight, healthy weight, overweight, or obese.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

• \( weight \) — Weight in kilograms (kg)
• \( height \) — Height in meters (m)

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

3. Importance of BMI Calculation

Details: BMI-for-age is the most widely used indicator to screen for potential weight problems in children and teens. It provides a reliable indicator of body fatness for most children and teens.

4. Using the Calculator

Tips: Enter weight in kg, height in meters, age in years (2-19), and select gender. The calculator will show the BMI value and CDC growth chart category.

5. Frequently Asked Questions (FAQ)

Q1: Why is BMI different for children than adults?
A: Children's body composition varies as they grow, and between boys and girls. BMI-for-age accounts for these differences.

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

Q3: How often should BMI be checked in children?
A: The AAP recommends BMI screening annually from age 2 through adolescence.

Q4: Are there limitations to BMI?
A: BMI doesn't directly measure body fat and can be misleading for muscular teens or those with different body compositions.

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