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. BMI 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 (kg)
• \( height \) — Height in meters (m)

Explanation: BMI is calculated by dividing weight in kilograms by the square of height in meters.

3. Importance of BMI Calculation

Details: BMI is a simple, inexpensive screening method for weight category—underweight, healthy weight, overweight, and obesity. It correlates with more direct measures of body fat and is strongly associated with various metabolic and disease outcomes.

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, first convert to metric units.

5. Frequently Asked Questions (FAQ)

Q1: What are the standard BMI categories?
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 those with muscular builds, and underestimate body fat in older persons 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: What are the health risks associated with high BMI?
A: Higher BMI is associated with increased risk of heart disease, stroke, type 2 diabetes, and certain cancers.

Q5: Should children use this calculator?
A: Children and teens need age- and sex-specific percentiles rather than the adult categories shown here.