1. What is BMI?

Body Mass Index (BMI) is a person's weight in kilograms divided by the square of height in meters. This NIH-approved calculator uses pounds and inches for convenience in the US population.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula adapted for pounds and inches:

Where:

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

Explanation: The formula calculates body mass index by adjusting weight for height squared, with a conversion factor for imperial units.

3. Importance of BMI Calculation

Details: BMI provides a simple numeric measure of body fatness for most people and is used to screen for weight categories that may lead to health problems.

4. Using the Calculator

Tips: Enter weight in pounds and height in inches. For accurate results, measure height without shoes and weight with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: What are the standard 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 with lost muscle mass.

Q3: Why use 703 in the formula?
A: This converts the metric formula (kg/m²) to work with pounds and inches (1 kg/m² ≈ 703 lb/in²).

Q4: What's a healthy BMI range?
A: For most adults, 18.5 to 24.9 is considered healthy, though individual factors matter.

Q5: Should children use this calculator?
A: No, children need age- and sex-specific BMI percentile calculations.