1. What is BMI?

Body Mass Index (BMI) is a simple index of weight-for-height that is commonly used to classify underweight, 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
• \( height \) — Height in meters

Age Adjustment: For adults (20+ years), standard categories apply. For children and teens, BMI is age- and sex-specific and should be plotted on growth charts.

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, height in meters, and age in years. For children under 20, consult pediatric growth charts for accurate interpretation.

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), Obese (≥30).

Q2: Is BMI accurate for athletes?
A: BMI may overestimate body fat in athletes with high muscle mass and underestimate it in older people with lost muscle mass.

Q3: How does BMI interpretation differ for children?
A: Children's BMI is plotted on sex-specific growth charts to determine percentiles based on age.

Q4: What is a healthy BMI for older adults?
A: Some studies suggest BMI of 23-27 may be optimal for older adults rather than the standard 18.5-24.9 range.

Q5: Should BMI be the only measure of healthy weight?
A: No, waist circumference and other measures of body composition should also be considered.