Home » Why Loss Weight? » Am I a Candidate for Obesity Surgery? » Check your BMI Check your BMI Weight kg Height cm BMI = NaN kg/m2 For your height, the upper limit of your ideal weight range is: 0kg (0st 0lbs), BMI = 25 kg/m2 BMI Definitions BMI (kg/m2) Underweight < 18 Healthy weight 18 - 25 Overweight 25 - 30 Obese (Class I) 30 - 35 Severely Obese (Class II) 35 - 40 Morbidly Obese (Class III) 40 and over