1. What is Body Mass Index?

Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age.

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 index by dividing weight in kilograms by the square of height in meters.

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. However, it should be used as a screening tool rather than a diagnostic of body fatness or health.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and age in years. All values must be valid (weight > 0, height > 0, age between 1-120).

5. Frequently Asked Questions (FAQ)

Q1: Why is age important in BMI calculation?
A: For children and teens, BMI interpretation is age- and sex-specific because the amount of body fat changes with age and differs between boys and girls.

Q2: What are the standard BMI categories for adults?
A: Underweight: <18.5, Normal weight: 18.5-24.9, Overweight: 25-29.9, Obesity: 30 or greater.

Q3: Are there limitations to BMI?
A: Yes, BMI doesn't account for muscle mass, bone density, overall body composition, and racial/sex differences. Athletes may have a high BMI but not have excess body fat.

Q4: How is BMI different for children?
A: For children, BMI is plotted on growth charts to determine the corresponding BMI-for-age percentile. These percentiles indicate how a child's BMI compares to others of the same age and sex.

Q5: Should BMI be the only measure of healthy weight?
A: No, waist circumference, diet, physical activity, and family history should also be considered when evaluating health risks associated with weight.