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 BMI result must be plotted on a gender-specific BMI-for-age growth chart to determine the percentile.

3. Importance of BMI Calculation

Details: BMI screening helps identify potential weight problems in children. However, it's not a diagnostic tool - further assessment is needed to determine if excess fat is a problem.

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?
A: Children's body composition varies by age and sex, so BMI must be interpreted relative to other children of the same age and sex.

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

Q3: When should BMI be measured?
A: NSW Health recommends regular BMI assessments as part of routine child health checks.

Q4: Are there limitations to BMI?
A: BMI doesn't distinguish between muscle and fat, and may not be accurate for very muscular children or those with certain medical conditions.

Q5: Where can I find growth charts?
A: NSW Health provides gender-specific BMI-for-age growth charts for clinical use.