BMI, or Body Mass Index, is a widely used measure to assess body weight in relation to height. It is calculated by dividing an individual's weight in kilograms by their height in meters squared (kg/m²). BMI categorizes individuals into different classifications, including underweight, normal weight, overweight, and obese. While BMI can serve as a useful screening tool, it does not account for factors such as muscle mass or fat distribution, which means it may not always accurately reflect an individual's health status. Therefore, it should be used alongside other indicators for a comprehensive health assessment.