1. What is BMI for Children?

BMI (Body Mass Index) is a measure that adjusts weight for height. For children and teens, BMI is age- and sex-specific and is referred to as BMI-for-age. This calculator uses Australian growth charts specifically for girls.

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 compared against Australian growth reference data for girls to determine the percentile category.

3. Importance of BMI Calculation

Details: BMI-for-age is the recommended measure for assessing weight status in children and teens. It helps identify potential weight problems that may lead to health issues.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and age in years (2-18 years). Measurements should be as accurate as possible for reliable results.

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 percentile categories?
A: Underweight (<5th), Healthy weight (5th-85th), Overweight (85th-95th), Obese (≥95th percentile).

Q3: How often should BMI be checked in children?
A: The Australian guidelines recommend measuring BMI at least once per year as part of routine health checks.

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

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