About BMI Calculator (WHO Standard)
The Body Mass Index (BMI) is the most widely used diagnostic tool in the world for characterizing weight levels in relation to height. Developed in the 19th century by Adolphe Quetelet, it remains the standard screening metric for the World Health Organization (WHO) and CDC.
The Formula
BMI = Weight (kg) / Height (m)²
It generates a simple two-digit number, typically between 15 and 40.
Interpretation Categories
- Underweight: BMI < 18.5
- Normal Weight: BMI 18.5 – 24.9
- Overweight: BMI 25 – 29.9
- Obesity: BMI ≥ 30
Limitations
Muscle vs. Fat: BMI makes no distinction between lean mass and fat. A heavyweight boxer or bodybuilder might have a BMI of 32 ("Obese") despite having 8% body fat and perfect metabolic health. Conversely, the elderly may have a "Normal" BMI but low muscle mass ("Skinny Fat"). BMI is a population-level tool, not a perfect individual diagnosis.