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BMI calculator
Body mass index is the starting point for most bariatric eligibility criteria. It is a rough measure, not a verdict — but it tells you which conversation you are having. Enter your weight and you will also see the average result reported for each treatment.
Starting at —, here is what the averages look like
Each figure below is the average loss of total body weight reported in published trials and series, typically measured over the first one to two years. Roughly half of patients do better than this and half do worse, and the spread in both directions is wide. These are not a prediction for you, and no result can be guaranteed.
| Treatment | Relative size | Average pounds lost |
Weight after |
|---|
Add your height above and each row will also show the BMI you would land at.
Surgery and medication are listed together, most weight lost to least, but they are not equivalent. Medication results hold only while you stay on the medication, and regain is common after stopping; a surgical result comes from a permanent change in anatomy. The gastric band figure is an average of reported results — long-term averages fall lower still, as bands are loosened, fail, or come out.
This calculator runs entirely in your browser. Nothing you enter is sent anywhere or stored.
What your number means for surgery
In 2022, the American Society for Metabolic and Bariatric Surgery and the International Federation for the Surgery of Obesity updated eligibility guidance that had been unchanged since 1991. Under current guidelines, surgery is considered appropriate at:
- BMI 35 or above — regardless of whether other conditions are present
- BMI 30 to 34.9 — when metabolic disease such as type 2 diabetes is present
- Lower thresholds for patients of Asian descent, where metabolic disease develops at lower BMI
Your insurance may use different numbers. Many plans still apply the older 1991 criteria — BMI 40, or 35 with a qualifying condition — and most require a documented supervised weight loss period first. Medical eligibility and insurance approval are separate questions, and we work through both.
Where BMI falls short
BMI is a ratio of weight to height. It does not know the difference between muscle and fat, it does not account for where fat is distributed, and it performs differently across ethnic groups and body types. A muscular person can land in the obese range while being metabolically healthy. Someone with a normal BMI can carry significant visceral fat.
It remains useful because it is simple, reproducible, and the basis of nearly every published guideline and insurance policy. Treat it as the opening question rather than the answer. Your blood sugar, blood pressure, sleep study, joint pain, and lipid panel all matter at least as much in deciding whether surgery makes sense for you.
And if your number falls below the surgical thresholds, or you simply do not want an operation, that is not the end of the conversation — medical weight loss covers a good deal of that ground.
Numbers are a starting point. The conversation is the real thing.
Bring your BMI, your history, and your questions to a full-hour consultation with Dr. Geller.