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. BMI 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
• \( height \) — Height in meters

Python Example:

def calculate_bmi(weight_kg, height_m):
    bmi = weight_kg / (height_m ** 2)
    return round(bmi, 1)

# Example usage
weight = 70  # kg
height = 1.75  # meters
bmi = calculate_bmi(weight, height)
print(f"BMI: {bmi}")

3. BMI Categories

Standard Categories:

• Underweight: BMI less than 18.5
• Normal weight: BMI 18.5 to 24.9
• Overweight: BMI 25 to 29.9
• Obese: BMI 30 or greater

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).

5. Frequently Asked Questions (FAQ)

Q1: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and underestimate it in older people who have lost muscle mass.

Q2: What are the limitations of BMI?
A: BMI doesn't account for muscle mass, bone density, overall body composition, or racial/sex differences.

Q3: How often should I check my BMI?
A: For most adults, checking every few months is sufficient unless you're actively trying to change your weight.

Q4: Is BMI different for children?
A: Yes, children's BMI is age- and sex-specific and is interpreted using percentile charts.

Q5: What's a healthy BMI range?
A: For most adults, 18.5 to 24.9 is considered healthy, but individual factors should be considered.