1. What is BMI?

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, normal weight, overweight and obesity in adults and children. 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:

• \( weight \) — 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 obtain a percentile ranking.

3. Importance of BMI Calculation for Children

Details: BMI is the most widely accepted method used to screen for underweight, healthy weight, overweight, and obesity in children and teens aged 2-19 years. Tracking growth patterns over time can help identify potential weight concerns.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For printable growth charts, visit the CDC website and plot the calculated BMI against age- and sex-specific percentiles.

5. Frequently Asked Questions (FAQ)

Q1: How is BMI different for children vs adults?
A: For adults, BMI categories are fixed. For children, BMI is compared to percentiles for children of the same sex and age.

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

Q3: Where can I find growth charts?
A: CDC provides printable BMI-for-age growth charts for boys and girls on their website.

Q4: How often should BMI be calculated for children?
A: Pediatricians typically calculate BMI at all routine check-ups from age 2 through 19.

Q5: Are there limitations to BMI for children?
A: BMI doesn't distinguish between fat and muscle mass. Athletic children may have high BMI without excess fat.