1. What is BMI for Age?

BMI-for-age is a screening tool that assesses whether a child has a healthy weight for their height, age and sex. 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 adjusted for age and sex:

Where:

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

Explanation: The result is compared to CDC growth charts to determine the percentile for girls of the same age.

3. Importance of BMI Percentile

Details: BMI percentiles are the most commonly used indicator to assess the size and growth patterns of children in the United States. Percentiles show how a child's BMI compares to other children of the same sex and age.

4. Using the Calculator

Tips: Enter weight in kg, height in meters, and age in years (2-20 years). For accurate results, measurements should be taken with minimal clothing and no shoes.

5. Frequently Asked Questions (FAQ)

Q1: What do the percentiles mean?
A: Below 5th percentile = underweight; 5th to 85th = healthy weight; 85th to 95th = overweight; 95th and above = obese.

Q2: 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.

Q3: How often should BMI be checked in children?
A: The American Academy of Pediatrics recommends BMI screening annually from age 2.

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

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