BMI (Body Mass Index)

BMI (Body Mass Index) is a numerical measure derived from a person’s weight and height—calculated as weight in kilograms divided by height in metres squared—and is used to categorize underweight, normal weight, overweight, and obesity. It provides a quick, population-level estimate of body fat but does not directly measure body composition or fat distribution, so it can misclassify very muscular people, growing children, pregnant patients or those with atypical body proportions.

In the context of plastic surgery, BMI (Body Mass Index) is commonly used during preoperative assessment because higher BMI can be associated with increased risks of complications such as wound healing problems, infection and anesthesia-related issues; this may influence surgical planning and discussions about optimizing health before an operation. Despite its usefulness as a screening tool, BMI is only one part of a comprehensive evaluation that includes medical history, comorbidities, functional status and lifestyle factors to determine individual risk and expected outcomes.