1. What is BMI?

Body Mass Index (BMI) is a simple calculation using a person's height and weight. The formula is BMI = kg/m² where kg is a person's weight in kilograms and m² is their height in meters squared. It provides a reliable indicator of body fatness for most people.

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 equation divides weight by the square of height to account for the relationship between height and body surface area.

3. Importance of BMI Calculation

Details: BMI is a simple, inexpensive screening method for weight category—underweight, healthy weight, overweight, and obesity. It helps assess risk for diseases that can occur with more body fat.

4. Using the Calculator

Tips: Enter weight in kilograms and height in meters. For height, you can convert from cm by dividing by 100 (e.g., 175 cm = 1.75 m). All values must be valid (weight > 0, height > 0).

5. Frequently Asked Questions (FAQ)

Q1: What are the 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 people who have lost muscle mass.

Q3: Why use the 2019 version?
A: The 2019 reference maintains consistency with WHO standards while being optimized for printable formats.

Q4: Should children use this calculator?
A: No, children and teens need age- and sex-specific percentiles rather than adult categories.

Q5: What's next after calculating BMI?
A: Consult a healthcare provider for further assessment if BMI is outside normal range.