1. What is 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 BMI formula:

Where:

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

Explanation: The formula calculates body mass per unit of surface area, providing a standardized way to compare weights across different heights.

3. Importance of BMI Calculation

Details: BMI provides a simple numeric measure that helps identify potential weight problems in adults. While it doesn't measure body fat directly, research has shown it correlates with direct measures of body fat.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For height in centimeters, divide by 100 (e.g., 175 cm = 1.75 m). All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

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

Q2: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and underestimate it in older people who have lost muscle mass.

Q3: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI percentiles.

Q4: What's a healthy BMI range?
A: For most adults, 18.5 to 24.9 is considered healthy.

Q5: Are there better measures than BMI?
A: Waist circumference and body fat percentage may provide additional useful information.