1. What is BMI for Children and Teens?

BMI-for-age is the measure used for children and teens (ages 2-19) because it accounts for the fact that children are still growing and their body composition changes as they age. The CDC provides sex-specific growth charts to interpret BMI values for children.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

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

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

3. Importance of BMI Calculation

Details: BMI is a reliable indicator of body fatness for most children and teens. It is used to screen for weight categories that may lead to health problems.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why is BMI different for children than adults?
A: Children's body composition varies by age and sex, so BMI must be compared against growth charts specific to their age and gender.

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

Q3: When should BMI be measured for children?
A: The AAP recommends BMI screening at least annually for all children ages 2 and older.

Q4: Are there limitations to BMI for children?
A: BMI doesn't distinguish between fat and muscle, so muscular children may have high BMI without excess fat.

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