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. In Australia, it's used as a screening tool for weight categories.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

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

For adults (18+ years): The result is categorized according to standard BMI ranges.

For children (2-17 years): BMI should be plotted on age- and sex-specific percentile charts.

3. Importance of BMI Calculation

Details: BMI provides a useful population-level measure of overweight and obesity. It's 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 in years, and select gender. For accurate results, measure height without shoes and weight with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: What are the Australian BMI categories for adults?
A: Underweight (<18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obese (≥30).

Q2: How is BMI interpreted for children?
A: Children's BMI is compared with age- and sex-specific percentiles: Underweight (<5th), Healthy weight (5th-85th), Overweight (85th-95th), Obese (>95th).

Q3: What are the limitations of BMI?
A: BMI doesn't distinguish between muscle and fat, and may not be accurate for athletes, pregnant women, or certain ethnic groups.

Q4: Is BMI different for different ethnicities?
A: Some populations (e.g., Asian, Pacific Islander) may have different health risks at lower BMI thresholds.

Q5: Where can I find Australian BMI percentile charts?
A: The Australian Government Department of Health provides growth charts including BMI-for-age percentiles.