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 height squared, providing a standardized measure for comparing body 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 not a direct measure of body fat, it correlates with more direct measures of body fat and is a quick screening tool for weight categories that may lead to health problems.

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), Obese (≥30).

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

Q3: Should BMI be interpreted differently for different populations?
A: Yes, some ethnic groups have different associations between BMI, percentage of body fat, and health risks.

Q4: What are the limitations of BMI?
A: BMI doesn't distinguish between muscle and fat mass, doesn't account for fat distribution, and may not be accurate for athletes, pregnant women, or the elderly.

Q5: Should children use the same BMI categories?
A: No, children and teens need BMI-for-age percentiles that consider growth patterns and sex differences.