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 provides a useful population-level measure of 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

Explanation: BMI correlates fairly well with body fat in most people, though it doesn't directly measure body fat.

3. Importance of BMI Calculation

Details: BMI is important because it helps identify potential weight problems in adults. However, it should be considered along with other measurements like waist circumference.

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: What are the BMI categories?
A: Underweight (<18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obesity (≥30).

Q2: Does BMI differ by age?
A: BMI interpretation is generally the same for all adults, though body composition changes with age.

Q3: What are limitations of BMI?
A: BMI doesn't account for muscle mass, bone density, overall body composition, or racial/ethnic differences.

Q4: Is BMI accurate for athletes?
A: BMI may overestimate body fat in athletes with high muscle mass and underestimate it in older people with less muscle mass.

Q5: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI percentiles rather than adult categories.