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 equation:

Where:

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

Explanation: BMI is calculated by dividing weight in kilograms by height in meters squared. The result is categorized into standard ranges.

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 weight-related health problems.

4. Using the Calculator

Tips: Enter weight in kilograms, height in meters, and optionally age. All values must be valid (weight > 0, height > 0, age between 0-120 if provided).

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 underestimate it in older persons who have lost muscle mass.

Q3: Why include age in the calculator?
A: While age doesn't affect BMI calculation, it helps provide age-appropriate interpretation of results.

Q4: What's a healthy BMI for older adults?
A: For adults over 65, a BMI between 23-29 may be healthier than lower ranges.

Q5: Should children use this calculator?
A: Children need BMI-for-age percentiles rather than adult categories. This calculator is for adults.