1. What is BMI?

Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. It provides a simple numeric measure of a person's thickness or thinness.

2. How Does the Calculator Work?

The calculator uses the BMI formula adapted for UK stone measurements:

Where:

• \( weight \) — Weight in stones (1 stone = 14 pounds)
• \( feet \) — Height in feet component
• \( inches \) — Height in inches component
• 703 — Conversion factor (kg/m² to lbs/in²)

Explanation: The formula converts stone weight to pounds, then calculates BMI using standard imperial units.

3. Importance of BMI Calculation

Details: BMI is widely used as a screening tool to identify possible weight problems in adults. It helps categorize individuals as underweight, normal weight, overweight, or obese.

4. Using the Calculator

Tips: Enter weight in stones (e.g., 11.5), height in feet and inches (e.g., 5 feet 7 inches). All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

Q1: What are the BMI categories?
A: Underweight (<18.5), Normal (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 people with lost muscle mass.

Q3: Why use stone measurements?
A: This calculator uses stone units which are commonly used in the UK for body weight measurements.

Q4: How often should I check my BMI?
A: Periodic checks (every few months) can help track weight changes, but daily fluctuations are normal.

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