1. What is BMI?

BMI (Body Mass Index) 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: 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 a simple, inexpensive screening tool for weight category—underweight, healthy weight, overweight, and obesity. While it doesn't measure body fat directly, research has shown that BMI correlates to 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 (BMI < 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), and Obese (≥30).

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

Q3: What's a healthy BMI range?
A: For most adults, an ideal BMI is in the 18.5 to 24.9 range. However, optimal BMI may vary by age, ethnicity and other factors.

Q4: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI calculations that account for their growing bodies.

Q5: What are the limitations of BMI?
A: BMI doesn't distinguish between muscle and fat, doesn't account for fat distribution, and may not be accurate for certain populations like athletes, pregnant women, or the elderly.