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 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 standard BMI formula:

Where:

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

Age Factor: The interpretation of BMI values varies by age. For adults (20+ years), standard categories apply. For children and teens, BMI is interpreted relative to age and sex-specific percentiles.

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, height in meters, and age in years. All values must be valid (weight > 0, height > 0, age between 1-120).

5. Frequently Asked Questions (FAQ)

Q1: 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.

Q2: What are the standard BMI categories for adults?
A: Underweight (<18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obese (≥30).

Q3: How is BMI different for children?
A: For children, BMI is age and sex-specific and is referred to as BMI-for-age, with growth charts used for interpretation.

Q4: What are the limitations of BMI?
A: BMI doesn't distinguish between muscle and fat, and doesn't account for fat distribution, which is important for health risks.

Q5: Should BMI be the only measure of healthy weight?
A: No, waist circumference and other risk factors should also be considered for a complete health assessment.