1. What is BMI?

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, healthy weight, overweight and obesity in adults. It is calculated by dividing weight in kilograms by the square of height in meters.

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)

Interpretation: The resulting number is compared against standard categories to assess weight status.

3. Importance of BMI Calculation

Details: BMI provides a simple numeric measure of a person's thickness or thinness, allowing health professionals to discuss weight problems more objectively with their patients.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For best accuracy, measure weight without heavy clothing and height without shoes.

5. Frequently Asked Questions (FAQ)

Q1: What are the BMI categories?
A: Underweight (<18.5), Healthy weight (18.5-24.9), Overweight (25-29.9), Obese (≥30).

Q2: Is BMI accurate for everyone?
A: BMI may not be accurate for athletes (high muscle mass), pregnant women, or the elderly (height changes).

Q3: How often should I check my BMI?
A: For most adults, checking every 3-6 months is sufficient unless actively trying to change weight.

Q4: What's a healthy BMI range for New Zealanders?
A: The same categories apply, though Māori and Pacific people may have different health risks at the same BMI.

Q5: Should children use this calculator?
A: No, children need age- and sex-specific BMI percentile charts.