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 the weight in kilograms divided by the square of the height in meters (kg/m²).

2. How is BMI Calculated?

The BMI formula is:

Where:

• Weight — in kilograms (kg)
• Height — in meters (m)

Note: For height in centimeters, first convert to meters by dividing by 100.

3. Importance of BMI

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 your weight in kilograms and height in centimeters. 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 not accurately reflect body fat in athletes (who may have high muscle mass) or the elderly (who may have lost muscle mass).

Q3: Why can't BMI be calculated without height?
A: BMI is a ratio of weight to height squared, so both measurements are essential for the calculation.

Q4: What's a healthy BMI range?
A: For most adults, a BMI between 18.5 and 24.9 is considered healthy.

Q5: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI percentiles.