1. What is BMI for Children?

Body Mass Index (BMI) is a measure that adjusts body weight for height. For children, BMI is age and sex-specific and is compared to growth charts to determine weight status percentiles.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

The result is then compared to New Zealand-specific growth charts to determine the child's weight status percentile.

3. Importance of BMI Calculation

Details: BMI screening helps identify children who are underweight, overweight, or obese. Early identification allows for timely intervention and healthy lifestyle promotion.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and age between 2-18 years. For most accurate results, measure height without shoes and weight with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: Why is BMI different for children than adults?
A: Children's body composition changes with age and differs between boys and girls, so BMI must be interpreted relative to age and sex-specific norms.

Q2: What are the BMI categories for NZ children?
A: Categories are based on percentiles: Underweight (<3rd), Healthy weight (3rd-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 3rd percentile or above the 85th percentile, or if there are sudden changes.

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

Q5: Where can I find NZ growth charts?
A: The NZ Ministry of Health provides growth charts based on WHO standards at health.govt.nz.