1. What is BMI-for-age?

BMI-for-age is a measure that accounts for a child's age and sex when assessing their body mass index. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age. This calculator uses CDC growth charts for boys aged 2-20 years.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula adjusted for age and sex:

Where:

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

Explanation: The result is then plotted on CDC growth charts to determine the child's BMI percentile for age.

3. Importance of BMI Calculation

Details: BMI-for-age is the most common indicator used to screen for overweight and obesity in children and teens. It can be an early warning sign of potential weight problems.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and exact age in years. For accurate results, measurements should be taken by a healthcare professional.

5. Frequently Asked Questions (FAQ)

Q1: Why use BMI-for-age instead of regular BMI?
A: Children's body composition changes as they grow, so BMI must be interpreted relative to other children of the same age and sex.

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

Q3: How often should children's BMI be checked?
A: The American Academy of Pediatrics recommends BMI screening at least annually for all children and adolescents.

Q4: Are there limitations to BMI-for-age?
A: BMI doesn't distinguish between fat and muscle mass. Athletic children may have high BMI due to muscle rather than fat.

Q5: What should I do if my child's BMI is high?
A: Consult with a pediatrician who can perform a complete assessment including growth history, family history, and other measurements.