1. What is BMI?

BMI (Body Mass Index) is a simple index of weight-for-height that is commonly used to classify underweight, normal weight, overweight and obesity in children and adults. For children, 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 should be compared to age and sex-specific percentile charts for Australian children.

3. Importance of BMI for Children

Details: BMI is an important screening tool for identifying potential weight problems in children. However, it's not a diagnostic tool - other factors like growth patterns and development must be considered.

4. Using the Calculator

Tips: Measure weight in kilograms and height in meters. For accurate results, measurements should be taken with minimal clothing and no shoes. The calculator is intended for children aged 2-18 years.

5. Frequently Asked Questions (FAQ)

Q1: What do the BMI percentiles mean?
A: For Australian children:
• Underweight: <5th percentile
• Healthy weight: 5th to <85th percentile
• Overweight: 85th to <95th percentile
• Obese: ≥95th percentile

Q2: Why use BMI for children instead of adults?
A: Children's body composition changes as they grow, so BMI must be interpreted relative to other children of the same age and sex.

Q3: Where can I find Australian BMI percentile charts?
A: The Australian Government Department of Health provides growth charts including BMI-for-age percentiles.

Q4: Are there limitations to BMI for children?
A: BMI doesn't distinguish between muscle and fat, so athletic children may appear overweight when they're not. Always consult a healthcare professional for interpretation.

Q5: How often should my child's BMI be checked?
A: Regular checks (e.g., annually) can help track growth patterns, but avoid excessive focus on weight which could lead to body image issues.