1. What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight to screen for weight categories that may lead to health problems. It's widely used by the NHS and other health organizations to assess weight status in adults.

2. How Does the Calculator Work?

The calculator uses the standard BMI formula:

Where:

• \( weight \) — Body weight in kilograms
• \( height \) — Height in meters

Explanation: The formula divides weight by the square of height to provide a standardized measure of body weight relative to height.

3. Importance of BMI Calculation

Details: BMI is a quick screening tool to identify possible weight problems in adults. While it doesn't measure body fat directly, research has shown it correlates with more direct measures of body fat.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For accurate results, measure weight without heavy clothing and height without shoes. All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

Q1: What are the NHS BMI categories for adults?
A: Underweight (<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 adults 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: Should children use this calculator?
A: No, children and teens need age- and sex-specific BMI calculations.

Q5: What should I do if my BMI is outside the normal range?
A: Consult with a healthcare provider for personalized advice and possible further assessment.