1. What is BMI?

Definition: Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women.

Purpose: It provides a simple numeric measure of a person's thickness or thinness, allowing health professionals to discuss weight problems objectively with their patients.

2. How Does the BMI Calculator Work?

The calculator uses the formula:

Where:

• \( BMI \) — Body Mass Index (kg/m²)
• \( W \) — Weight (kilograms)
• \( H \) — Height (meters)

Explanation: Your weight in kilograms is divided by the square of your height in meters.

3. BMI Categories

Details: According to NHS UK guidelines:

• Below 18.5 — Underweight
• 18.5-24.9 — Healthy weight
• 25-29.9 — Overweight
• 30 and above — Obese

4. Using the Calculator

Tips: Enter your weight in kilograms and height in meters. For example, 70 kg and 1.75 m.

5. Frequently Asked Questions (FAQ)

Q1: Is BMI accurate for everyone?
A: BMI may not be accurate for athletes (who have more muscle mass) or elderly people (who may have lost muscle mass).

Q2: How do I convert stones and pounds to kg?
A: 1 stone = 6.35 kg, 1 pound = 0.45 kg. For example, 11 stone 5 pounds = (11×6.35) + (5×0.45) ≈ 72.1 kg.

Q3: How do I convert feet and inches to meters?
A: 1 foot = 0.3048 m, 1 inch = 0.0254 m. For example, 5 feet 9 inches = (5×0.3048) + (9×0.0254) ≈ 1.75 m.

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

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