Gastric Sleeve Weight Loss Calculator: Expected Weight Month by Month After Sleeve Gastrectomy
Estimate your weight, BMI and percent of excess weight lost 3, 6, 12, 18 and 24 months and 5 years after gastric sleeve surgery, using published sleeve gastrectomy results.
How it works
BMI = weight (kg) ÷ height (m)² · “Ideal” weight = 25 × height (m)² · Excess weight = weight − ideal weight · Weight lost by month t = excess weight × %EWL(t) · Projected weight = starting weight − weight lost · %EWL(t): 33% at 3 months, 50.8% at 6, 59.6% at 12, 63.3% at 18, 63.6% at 24, 49% at 5 years
Bariatric surgeons usually report results as percent excess weight loss (%EWL): the share of the weight above a BMI of 25 that has been lost. After a sleeve gastrectomy most loss happens in the first 6 months, slows through the first year and levels off at 18–24 months. This calculator applies the mean %EWL of a published series of 141 consecutive sleeve patients (33% at 3 months, 50.8% at 6, 59.6% at 1 year, 63.3% at 18 months and 63.6% at 2 years) and the 5-year result of the SLEEVEPASS randomized trial (49%), with straight-line steps between the points. It then turns those percentages into your weight, BMI and percent of total body weight lost. Results vary a lot between people and between studies, so a second table shows your weight under other published series, from 44% to 86% excess weight loss at 2 years. People with a very high starting BMI tend to lose a smaller share of their excess weight. Unlike the general Weight Loss Timeline or Goal Weight Date calculators, which use a calorie deficit, this projection follows what sleeve patients actually lost after surgery.
Worked example
A person 66 in (5 ft 6 in, 1.676 m) tall who weighs 280 lb (127.0 kg) before surgery has a BMI of 127.0 ÷ 1.676² = 45.2. Ideal weight at BMI 25 is 25 × 1.676² = 70.3 kg (154.9 lb), so excess weight is 125.1 lb. One year after a sleeve, the typical excess weight loss is 59.6%: 125.1 × 0.596 = 74.6 lb lost, for a projected weight of about 205 lb, a BMI of 33.2 and 26.6% of starting weight lost. At 6 months the projection is 216 lb and at 2 years 200 lb.
Sources: SAGES abstract: Long-term follow-up after sleeve gastrectomy (141 patients, %EWL at 3–24 months) · Salminen et al., SLEEVEPASS randomized clinical trial, JAMA 2018 (5-year %EWL 49%) · Lehmann et al. 2014: %EWL after sleeve gastrectomy vs gastric banding (by BMI group) · Hoyuela 2017: Five-year outcomes of laparoscopic sleeve gastrectomy · Omni Calculator: Gastric sleeve weight loss (5 ft 6 in, 289 lb example)
Frequently asked questions
How much weight do you lose with a gastric sleeve?
On average about 60–70% of excess weight in the first 1–2 years. In one series of 141 patients the average was 33% of excess weight at 3 months, 51% at 6 months, 60% at 1 year and 64% at 2 years. In the SLEEVEPASS trial, 5 years after surgery patients had kept off 49% of their excess weight on average.
How much weight will I lose in the first 3 months after the sleeve?
In the series used here, patients had lost 33% of their excess weight by 3 months, about 11% a month. For someone with 120 lb (54 kg) of excess weight that is roughly 40 lb (18 kg) in 3 months. Loss is usually fastest in the first weeks, during the liquid and puréed diet stages, so the month-1 and month-2 values in the table are a straight-line estimate.
What does percent excess weight loss mean?
It is the weight you lost divided by your excess weight, the amount above a “healthy” weight usually defined as a BMI of 25. If you weigh 280 lb and your BMI-25 weight is 155 lb, your excess weight is 125 lb; losing 75 lb is 60% excess weight loss.
When does weight loss stop after a gastric sleeve?
Most people reach their lowest weight 12–24 months after surgery. After that, some regain is common: average excess weight loss in long-term studies falls from about 60–80% at 1–2 years to roughly 50–60% at 5 years.
Do people with a higher BMI lose more weight after the sleeve?
They usually lose more pounds or kilograms, but a smaller percentage of their excess weight. In one study patients starting at BMI 50–55 lost 34% of excess weight at 1 year, against 43–48% for BMI 35–50.
Related calculators
Educational projection based on average published results, not a prediction for any individual or medical advice. Your surgeon and bariatric team will set your goals, diet stages and follow-up; seek care promptly for persistent vomiting, chest or abdominal pain, fever or inability to keep fluids down after surgery.