A weight-to-height ratio used as a rough proxy for body fatness.
BMI is calculated as weight in kilograms divided by height in metres squared, and is used at a population level to categorise underweight, healthy weight, overweight, and obesity. In individuals, particularly athletes or those with high muscle mass, BMI can misclassify body composition because it cannot distinguish fat mass from lean mass; clinicians should interpret it alongside other measures (e.g. waist circumference, body fat percentage) rather than in isolation.
This guide was auto-drafted and is pending editorial review.