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.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

For children and teens (ages 2-19), the BMI is plotted on CDC growth charts to determine the BMI-for-age percentile.

Explanation: The percentile shows how a child's BMI compares to other children of the same age and sex.

3. Importance of BMI Percentiles for Children

Details: BMI percentiles are the most commonly used indicator to assess the size and growth patterns of children in the United States. They help identify potential weight problems that could lead to health issues.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, age in years, and select gender. For children under 2 years, different growth charts should be used.

5. Frequently Asked Questions (FAQ)

Q1: Why use BMI percentiles for children instead of regular BMI categories?
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 are the BMI percentile categories for children?
A: Underweight (<5th percentile), Healthy weight (5th to 85th percentile), Overweight (85th to 95th percentile), 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?
A: BMI doesn't directly measure body fat and may misclassify muscular individuals. It also doesn't account for differences in body composition between ethnic groups.

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