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 and children.

2. How Does the Calculator Work?

The calculator uses the 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 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 is an important indicator of health risks associated with being underweight or overweight.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. All values must be valid (weight > 0, height > 0). For children, BMI should be interpreted using age- and sex-specific percentiles.

5. Frequently Asked Questions (FAQ)

Q1: What is a healthy BMI range?
A: For adults, 18.5-24.9 is considered normal weight. For children, BMI is interpreted using age- and sex-specific growth charts.

Q2: Does BMI apply to everyone?
A: BMI may overestimate body fat in athletes and others with muscular builds, and may underestimate body fat in older persons and others who have lost muscle mass.

Q3: Why use BMI for children?
A: BMI for children is age- and sex-specific and is often referred to as BMI-for-age. It's a useful screening tool but not a diagnostic tool.

Q4: What are the limitations of BMI?
A: BMI doesn't directly measure body fat and doesn't account for factors like muscle mass, bone density, overall body composition, and racial and sex differences.

Q5: How often should BMI be measured in children?
A: The American Academy of Pediatrics recommends BMI screening at least annually for all children and adolescents.