1. What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared. BMI provides a simple numeric measure of a person's thickness or thinness.

2. How Does the Calculator Work?

The calculator uses the BMI formula:

Where:

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

Explanation: The formula divides a person's weight by the square of their height to categorize their weight status.

3. BMI Categories

Standard BMI Categories:

• 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 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 everyone?
A: BMI may not accurately reflect body fat in athletes (who have more muscle) or elderly (who may have lost muscle).

Q2: What's the difference between BMI for adults and children?
A: For children, BMI is age and sex-specific and expressed as a percentile rather than absolute values.

Q3: How often should I check my BMI?
A: For most adults, checking every few months is sufficient unless you're actively trying to change your weight.

Q4: Are there better measures than BMI?
A: Waist circumference and body fat percentage may provide additional useful information about health risks.

Q5: Can I use pounds and inches?
A: Yes, but the formula changes to: BMI = (weight in lbs × 703) / (height in inches)²