Body Mass Index (BMI) is a simple and widely used measurement that helps assess whether a person has a healthy body weight in relation to their height. It is calculated by dividing weight (in kilograms) by the square of height (in meters). BMI provides a quick indication of whether someone is underweight, within a normal range, overweight, or obese. While it is a useful screening tool, BMI does not directly measure body fat, muscle mass, or overall health. Factors such as age, gender, and body composition can influence how BMI should be interpreted. Therefore, it is best used as a general guideline rather than a definitive diagnosis, and should ideally be considered alongside other health indicators.