1. What is BMI?

BMI (Body Mass Index) is a measure that uses height and weight to estimate body fat. For children and youth, 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 result is then compared to Australian growth charts to determine the percentile for the child's age and gender.

3. Importance of BMI for Children

Details: BMI-for-age is the recommended measure for screening overweight and obesity in children and teens. It's important for identifying 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 with minimal clothing and no shoes.

5. Frequently Asked Questions (FAQ)

Q1: Why use BMI-for-age instead of regular BMI?
A: Children's body composition changes as they grow, so BMI must be interpreted relative to other children of the same age and sex.

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

Q3: When should I be concerned about my child's BMI?
A: Consult a healthcare provider if your child is below the 5th percentile or above the 85th percentile.

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

Q5: Where can I find official Australian growth charts?
A: The Australian Government Department of Health provides growth charts based on WHO standards.