Definition
BMI (Body Mass Index) is a measure of body fatness calculated from weight and height. The formula is weight (kg) divided by height (m) squared. It was devised in 1832 by Belgian statistician Adolphe Quetelet as a simple screening tool for population-level obesity assessment.
Classification Criteria
Under WHO standards, a BMI below 18.5 is underweight, 18.5-24.9 is normal, 25.0-29.9 is overweight, and 30.0 or above is obese. The Japan Society for the Study of Obesity classifies 25.0 and above as obese, applying a stricter threshold than the WHO.
Limitations and Caveats
BMI cannot distinguish between muscle mass and fat mass. A muscular person may have a high BMI with low health risk. Additionally, the same BMI can carry different risks depending on whether fat is visceral or subcutaneous. It remains a screening tool and should not be used as a definitive health assessment.
Global Ranking Context
MyRank uses BMI to show where you stand relative to the global population. Understanding that BMI thresholds vary by region helps you interpret your ranking more accurately and motivates informed health decisions.