1. What is BMI for Children?

Body Mass Index (BMI) is a measure that adjusts body weight for height. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age. It's a screening tool that may indicate whether a child is underweight, healthy weight, overweight, or obese.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

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

Note: For children, the raw BMI value should be plotted on a growth chart or compared to percentile tables that account for age and sex.

3. Importance of BMI Calculation

Details: BMI-for-age is the recommended measure for screening overweight and obesity 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 and height in meters. For accurate results, measure weight and height using standardized methods.

5. Frequently Asked Questions (FAQ)

Q1: How is children's BMI different from adults?
A: Children's BMI is interpreted relative to other children of the same age and sex, using percentile charts rather than fixed categories.

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

Q3: When should BMI be measured in children?
A: Regular BMI screening is recommended from age 2, at least annually.

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

Q5: Where can I find NZ-specific BMI charts?
A: The New Zealand Ministry of Health provides BMI-for-age growth charts based on WHO standards.