1. What is BMI-for-age?

BMI-for-age is a measure that takes into account a child's age and sex when assessing their Body Mass Index (BMI). For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

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

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

3. Importance of BMI Calculation

Details: BMI-for-age is the recommended measure for screening overweight and obesity in children and teens. It's a reliable indicator of body fatness for most children.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

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

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

Q3: When should BMI be measured in children?
A: The AAP recommends BMI screening at least annually starting at age 2.

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

Q5: Where can I find the CDC growth charts?
A: CDC growth charts are available on the CDC website for clinical use.