BMI calculator and weight-loss surgery eligibility
This BMI calculator gives a quick estimate of your weight relative to your height, the class it falls into, and whether the international criteria for bariatric surgery apply to you.
Your BMI
Send my result to the doctorHow the result is calculated
BMI = weight in kilograms ÷ (height in metres)². Classes follow the World Health Organization; eligibility follows the 2022 American Society for Metabolic and Bariatric Surgery (ASMBS) and International Federation for the Surgery of Obesity (IFSO) indications. BMI does not measure fat distribution or muscle mass and does not replace a medical assessment.
Criteria reviewed: October 2026
Frequently asked questions
Does BMI alone decide whether I need weight-loss surgery?
No. BMI is only a starting point. A surgeon also assesses related conditions such as diabetes, high blood pressure and sleep apnoea, previous weight-loss attempts, and your nutritional and psychological readiness before recommending surgery.
What is the minimum BMI for sleeve gastrectomy?
The 2022 ASMBS/IFSO guidelines generally recommend bariatric surgery from a BMI of 35, and it can be considered from 30 with a metabolic disease such as type 2 diabetes. The final decision follows an examination.
Is BMI accurate for athletes and older adults?
BMI can overestimate fat in very muscular people and underestimate it in older adults who have lost muscle. That is why it is combined with a waist measurement and a clinical assessment.
What should I do if my result meets the surgery criteria?
The next step is a consultation to assess your case and discuss the options that suit you — sleeve gastrectomy, gastric bypass, an intragastric balloon, or non-surgical treatment if that is the better fit.
References
- 2022 ASMBS and IFSO: Indications for Metabolic and Bariatric Surgery — Surgery for Obesity and Related Diseases
- Obesity and overweight — fact sheet — World Health Organization
This information is general education and does not replace a medical examination. Treatment decisions are made after assessing your case.
Have a question about your case?
Send your question and the clinic team will contact you to arrange a consultation, usually within the same working day.
- An honest assessment of your case
- A clear plan before any decision
- A detailed quote after examination