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 (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. Importance of BMI Calculation

Details: BMI is a simple, inexpensive screening method for weight category - underweight, healthy weight, overweight, and obesity. While BMI doesn't measure body fat directly, research has shown that BMI is moderately correlated with more direct measures of body fat.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For height, you can convert from centimeters by dividing by 100 (e.g., 175 cm = 1.75 m). All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

Q1: What are the standard 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 overestimate body fat in athletes and others with muscular builds, and may underestimate body fat in older persons and others who have lost muscle mass.

Q3: Should children use this calculator?
A: No, children and teens need age- and sex-specific percentiles because their body composition varies as they grow.

Q4: What are the health risks associated with high BMI?
A: Higher BMI is associated with increased risk of heart disease, high blood pressure, type 2 diabetes, gallstones, breathing problems, and certain cancers.

Q5: What are the limitations of BMI?
A: BMI doesn't account for muscle mass, bone density, overall body composition, and racial and sex differences.