1. What is Body Mass Index (BMI)?

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, overweight and obesity in adults. It is defined as the weight in kilograms divided by the square of the height in meters (kg/m²).

2. How Does the Calculator Work?

The calculator uses the WHO standard BMI formula:

Where:

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

Explanation: 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.

3. Importance of BMI Calculation

Details: BMI is widely used as a screening tool to identify possible weight problems in adults. However, it is not a diagnostic tool and should be used in conjunction with other assessments for a complete health evaluation.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For accurate results, measure weight without heavy clothing and height without shoes. All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

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

Q2: Is BMI accurate for everyone?
A: BMI may not be accurate for athletes (high muscle mass), elderly (loss of muscle mass), pregnant women, and children.

Q3: How often should I check my BMI?
A: For general monitoring, checking every 3-6 months is sufficient unless you're actively trying to change your weight.

Q4: What's the difference between BMI and body fat percentage?
A: BMI estimates body fat based on height and weight, while body fat percentage directly measures fat mass. Body fat percentage is more accurate but requires special equipment.

Q5: Can BMI be used for children?
A: For children and teens, BMI is age and sex-specific and is referred to as BMI-for-age. Different charts and percentiles are used.