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's calculated by dividing a person's weight in kilograms by the square of their height in meters (kg/m²). This calculator uses the imperial formula with pounds and inches.

2. How Does the Calculator Work?

The calculator uses the imperial BMI formula:

Where:

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

Explanation: The formula converts imperial measurements to produce the standard BMI value in kg/m².

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. All values must be valid (weight > 0, height > 0). For most accurate results, measure height without shoes and weight with minimal clothing.

5. Frequently Asked Questions (FAQ)

Q1: What are the BMI categories?
A: Underweight (BMI < 18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obese (≥30).

Q2: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and underestimate it in older persons who have lost muscle mass.

Q3: How often should I check my BMI?
A: For most adults, checking every 6-12 months is sufficient unless actively trying to change weight.

Q4: What's the difference between metric and imperial formulas?
A: They produce identical results - the imperial formula includes the 703 conversion factor to account for pounds and inches.

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