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 standard BMI formula:

Where:

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

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 an inexpensive and easy screening method for weight category—underweight, healthy weight, overweight, and obesity. It correlates moderately well with body fat percentage and can indicate potential health risks associated with different weight categories.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For accuracy, measure weight without heavy clothing and height without shoes. All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

Q1: What are the BMI categories for adults?
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 overestimate body fat in athletes and those with muscular build, and underestimate it in older persons who have lost muscle mass.

Q3: How often should I check my BMI?
A: For most adults, checking BMI annually is sufficient unless actively trying to lose or gain weight.

Q4: Does BMI apply to children?
A: Children's BMI is calculated the same way but interpreted differently using age and sex-specific percentiles.

Q5: What are healthy alternatives to BMI?
A: Waist circumference, waist-to-hip ratio, and body fat percentage measurements can provide additional information.