1. What is BMI?

Body Mass Index (BMI) 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 the weight in kilograms divided by the square of the height in meters.

2. How is BMI Calculated?

The BMI calculation formula is:

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. BMI Categories

Standard BMI Categories for Adults:

• 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

Note: For older adults (60+ years), slightly higher BMI values may be associated with better health outcomes.

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 positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Is BMI accurate for older adults?
A: BMI is a screening tool but may not reflect body composition changes in older adults who often lose muscle mass and gain fat.

Q2: What is a healthy BMI for a 60-year-old?
A: For older adults, a BMI between 23-29 may be healthier than lower values, as very low BMI is associated with higher mortality.

Q3: Does BMI account for muscle mass?
A: No, BMI doesn't distinguish between muscle and fat. Athletes may have high BMI without excess fat.

Q4: Should waist circumference be measured too?
A: Yes, waist measurement provides additional information about abdominal fat which is particularly important for health risks.

Q5: How often should BMI be checked?
A: For most adults, checking every 6-12 months is sufficient unless there are specific health concerns.