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 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 BMI formula:

Where:

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

Explanation: The formula calculates body mass per unit of surface area, providing a standardized way to compare body weights across different heights.

3. Importance of BMI Calculation

Details: BMI is a simple, inexpensive screening tool for weight categories that may indicate potential health problems. It helps identify potential weight problems in adults, though it doesn't diagnose body fatness or health directly.

4. Using the Calculator

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

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), Obese (≥30).

Q2: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes/muscular individuals and underestimate it in older people with lost muscle mass.

Q3: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI percentiles.

Q4: What are the health risks of high BMI?
A: Higher BMI is associated with increased risk of heart disease, diabetes, and certain cancers.

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