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 the weight in kilograms divided by the square of the 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: The formula calculates body mass per unit of height squared, providing a standardized measure of body composition.

3. Importance of BMI Calculation

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 weight in kilograms and height in meters. 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), Obesity (≥30).

Q2: Is BMI accurate for everyone?
A: BMI may not be accurate for athletes (high muscle mass), pregnant women, or the elderly (muscle loss).

Q3: How often should I check my BMI?
A: For most adults, checking every 6-12 months is sufficient unless actively trying to change weight.

Q4: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI percentiles rather than adult categories.

Q5: What's better than BMI for measuring body fat?
A: More precise methods include skinfold thickness measurements, bioelectrical impedance, DEXA scans, or underwater weighing.