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 kids, 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

Explanation: The formula calculates body mass per unit of height squared, providing a standardized measure for comparing individuals of different heights.

3. Importance of BMI Calculation for Kids

Details: BMI-for-age is the recommended measure for screening overweight and obesity in children and teens. It compares a child's BMI to growth charts that account for normal differences in growth patterns among kids of different ages and sexes.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For most accurate results, measure height without shoes and weight with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: How is children's BMI different from adults?
A: For children, BMI is plotted on growth charts to determine a percentile ranking based on age and sex, rather than using fixed cutoffs like adults.

Q2: What do the percentile ranges mean?
A: Generally, <5th percentile is underweight, 5th-85th is healthy weight, 85th-95th is overweight, and ≥95th is obese.

Q3: Why use both NSW and CDC tools?
A: Using both provides comprehensive assessment as they may use slightly different growth references and percentile calculations.

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

Q5: When should I consult a doctor about my child's BMI?
A: If your child is consistently below 5th or above 85th percentile, or if there are sudden changes in BMI percentile.