1. What is BMI?

Body Mass Index (BMI) is a measure that uses height and weight to estimate body fat. 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, the raw BMI value must be plotted on age- and sex-specific growth charts to determine the BMI percentile.

3. Importance of BMI Calculation for Children

Details: BMI-for-age is the recommended measure for screening overweight and obesity in children aged 2-18 years. It helps identify potential weight problems that may lead to health issues.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, age in years (2-18), and select gender. For accurate results, measurements should be taken by a health professional.

5. Frequently Asked Questions (FAQ)

Q1: Why is BMI different for children than adults?
A: Children's body composition varies by age and sex as they grow, so BMI must be interpreted relative to other children of the same age and sex.

Q2: What are the BMI categories for children?
A: Categories are based on percentiles: Underweight (<5th), Healthy weight (5th-<85th), Overweight (85th-<95th), Obese (≥95th).

Q3: When should BMI be measured in children?
A: NSW Health recommends annual BMI assessment for all children aged 2-18 years as part of routine health checks.

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

Q5: Where can I find NSW Health growth charts?
A: NSW Health provides standardized growth charts for plotting BMI-for-age at health facilities and on their website.