1. What is BMI?

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, normal weight, overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of their 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 measure for comparing individuals of different heights.

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 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 standard 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 accurately reflect body fat in athletes (high muscle mass), the elderly (muscle loss), or certain ethnic groups.

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

Q4: What are healthy BMI ranges for Asians?
A: Many Asian countries use lower thresholds (e.g., overweight ≥23, obese ≥27.5) due to higher health risks at lower BMI.

Q5: What's better than BMI for measuring health?
A: Waist circumference, body fat percentage, and waist-to-hip ratio provide additional useful information about health risks.