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 formula divides a person's weight by the square of their height to categorize their weight status.

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. All values must be valid (weight > 0, height > 0). For pounds and inches, convert first (1 kg = 2.2 lbs, 1 m = 39.37 inches).

5. Frequently Asked Questions (FAQ)

Q1: What are the BMI categories?
A: Underweight (<18.5), Normal weight (18.5-24.9), Overweight (25-29.9), Obesity (≥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 metric units?
A: The standard BMI formula uses kg/m². For imperial units, the formula is [weight (lbs) / height (in)²] × 703.

Q4: What's a healthy BMI range?
A: For most adults, 18.5 to 24.9 is considered healthy, but optimal range may vary by age and ethnicity.

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