1. What is BMI?

Body Mass Index (BMI) is a measure of body fat based on height and weight that applies to adult men and women. It is a simple, inexpensive, and non-invasive method to screen for weight categories that may lead to health problems.

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)
• \( BMI \) — Body Mass Index in kg/m²

Explanation: BMI provides a reliable indicator of body fatness for most people and is used to screen for weight categories that may lead to health problems.

3. CDC Adult BMI Categories

CDC Classification:

• Underweight: BMI less than 18.5
• Normal weight: BMI 18.5 - 24.9
• Overweight: BMI 25 - 29.9
• Obese: BMI 30 or greater

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: Is BMI accurate for everyone?
A: BMI may overestimate body fat in athletes and others with muscular build, and underestimate body fat in older persons who have lost muscle mass.

Q2: What are the limitations of BMI?
A: BMI does not account for muscle mass, bone density, overall body composition, and racial and sex differences.

Q3: Can children use this calculator?
A: No, this calculator is for adults only. Children and teens need age and sex-specific BMI percentiles.

Q4: How often should I check my BMI?
A: For general monitoring, checking every 3-6 months is sufficient unless you're actively trying to change your weight.

Q5: What's a healthy BMI range?
A: For most adults, a BMI between 18.5 and 24.9 is considered healthy and associated with the lowest health risks.