1. What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = 703 × weight (lb) / [height (in)]². The result is used to categorize whether a person is underweight, normal weight, overweight, or obese.

2. How Does the Calculator Work?

The calculator uses the BMI equation:

Where:

• \( Weight \) — Body weight in pounds (lb)
• \( Height \) — Height in inches (in)
• 703 — Conversion factor (kg/m²)/(lb/in²)

Explanation: BMI provides a simple numeric measure of a person's thickness or thinness, allowing health professionals to discuss weight problems objectively.

3. Importance of BMI Calculation

Details: BMI is used to screen for weight categories that may lead to health problems. While it doesn't measure body fat directly, research has shown BMI correlates with direct measures of body fat.

4. Using the Calculator

Tips: Enter weight in pounds and height in inches. All values must be valid (weight > 0, height > 0). For most adults, BMI provides a good estimate of weight-related health risks.

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: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and underestimate it in older people who have lost muscle mass.

Q3: Why use 703 in the formula?
A: 703 is the conversion factor needed when using pounds and inches (kg/m²)/(lb/in²).

Q4: Should children use this calculator?
A: Children's BMI is interpreted differently using age- and sex-specific percentiles rather than these fixed categories.

Q5: What's a healthy BMI range?
A: For most adults, 18.5 to 24.9 is considered healthy, though optimal range may vary by individual factors.