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 BMI equation:

Where:

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

Explanation: The formula divides the weight by the square of the height to account for the relationship between height and body surface area.

3. Importance of BMI Calculation

Details: BMI is used to screen for weight categories that may lead to health problems. It's a simple, inexpensive method of classifying underweight, normal weight, overweight and obesity.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. All values must be valid (weight > 0, height > 0). For pounds and inches, convert first (1 kg = 2.2 lbs, 1 m = 39.37 inches).

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 overestimate body fat in athletes and underestimate it in older people who have lost muscle mass.

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

Q4: What are the limitations of BMI?
A: Doesn't distinguish between muscle and fat, doesn't account for fat distribution, and may not be accurate for certain ethnic groups.

Q5: How would this be implemented in Python?
A: def calculate_bmi(weight, height): return round(weight / (height ** 2), 1)