1. What is BMI?

Definition: Body Mass Index (BMI) is a value derived from the mass (weight) and height of a person.

Purpose: The BMI is a simple, inexpensive screening method for weight category—underweight, healthy weight, overweight, and obesity.

2. How Does the BMI Calculator Work?

The calculator uses the formula:

Where:

• \( BMI \) — Body Mass Index (kg/m²)
• \( W \) — Weight (kilograms)
• \( H \) — Height (meters)

Explanation: Your weight in kilograms is divided by the square of your height in meters.

3. BMI Categories

Details:

• Underweight: BMI < 18.5
• Normal weight: BMI 18.5-24.9
• Overweight: BMI 25-29.9
• Obesity: BMI ≥ 30

4. Using the Calculator

Tips: Enter your weight in kilograms and height in meters. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: How accurate is BMI?
A: BMI is a useful screening tool but doesn't directly measure body fat or account for muscle mass, bone density, etc.

Q2: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI calculations.

Q3: What if I know my weight in pounds and height in inches?
A: Convert pounds to kg (divide by 2.205) and inches to meters (multiply by 0.0254) first.

Q4: Why is BMI important?
A: Higher BMI is associated with increased risk of various diseases like diabetes and heart disease.

Q5: Are there limitations to BMI?
A: Yes, athletes may have high BMI from muscle not fat, and elderly may have normal BMI but low muscle mass.