1. What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared. It provides a reliable indicator of body fatness for most people.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

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

Explanation: BMI is calculated by dividing weight in kilograms by the square of height in meters.

3. Importance of BMI Calculation

Details: BMI is a simple, inexpensive screening method for weight category—underweight, healthy weight, overweight, and obesity. It correlates with amount of body fat in most people.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and optionally age. 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 others with muscular builds, and underestimate body fat in older persons who have lost muscle mass.

Q3: How does age affect BMI interpretation?
A: For children and teens, BMI is age- and sex-specific. For adults, the same BMI categories apply to all ages.

Q4: What are healthy BMI ranges?
A: For most adults, 18.5 to 24.9 is considered healthy. However, optimal BMI may vary by age and ethnicity.

Q5: Should BMI be the only measure of health?
A: No. Waist circumference, diet, physical activity, and other factors should also be considered for a complete health assessment.