The qualifications for bariatric surgery are based largely on a calculation called your Body Mass Index or BMI.  This is a calculation based on your height and weight. Calculate your BMI using our tool. You may be a candidate for weight loss surgery if: Your BMI is 40 or greater with or without co-morbidities (medical conditions) Your BMI is 35 or greater with co-morbidities (medical conditions) Regardless of your BMI, bariatric surgery should be reserved for those who have tried non-surgical methods of weight-loss and have been unsuccessful.