1. What is BMI?

Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. BMI is an inexpensive and easy screening method for weight category—underweight, healthy weight, overweight, and obesity.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

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

Interpretation: For adults 20 years and older, BMI is interpreted using standard weight status categories that are the same for all ages and for both men and women.

3. Importance of BMI Calculation

Details: BMI is a reliable indicator of body fatness for most people. It is used to screen for weight categories that may lead to health problems but is not diagnostic of the body fatness or health of an individual.

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 CDC BMI categories for adults?
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 and others with muscular builds and underestimate it in older persons who have lost muscle mass.

Q3: Should children use this calculator?
A: No, children and teens need age- and sex-specific percentiles because their body composition varies as they grow.

Q4: What are the health risks of high BMI?
A: Higher BMI is associated with increased risk of heart disease, high blood pressure, type 2 diabetes, gallstones, and certain cancers.

Q5: What's a healthy BMI for older adults?
A: Some studies suggest BMI range of 23-29 may be healthier for older adults than the standard categories.