Gastric Sleeve Weight Loss Calculator

What Does This Calculator Estimate?

Bariatric surgery projections are based on excess weight loss, not total body weight. The calculator first computes body mass index (BMI) from height and weight, then determines excess weight above an ideal BMI of 24.9. Expected loss applies a procedure-specific percentage to that excess weight.

Procedure-Specific Loss Percentages

Typical mean excess weight loss estimates include roughly 30% for AspireAssist and gastric balloon, 40% for lap band, 65% for gastric bypass and duodenal switch, and 70% for gastric sleeve. Individual results vary with adherence, starting BMI, comorbidities, and postoperative follow-up. Confirm your starting BMI with the BMI Calculator or age-specific tools such as the BMI Calculator for Teens.

Timeline Milestones

The calculator shows projected weight at about 3 months (25% of expected loss), 6 months (50%), and 12 months (90%) after surgery. These are averages for counseling discussions, not guarantees for any single patient.

Typical Eligibility by BMI

Many programs consider bariatric surgery when BMI is 40 or higher, or BMI 35 or higher with obesity-related comorbidities. BMI 30 to 34.9 may be borderline depending on local criteria and comorbidity burden. Final eligibility requires multidisciplinary evaluation.

Frequently Asked Questions

How is excess weight calculated?

Excess weight equals current weight minus ideal weight at BMI 24.9 for the entered height. If current weight is below ideal, excess weight is treated as zero.

Why is gastric sleeve listed at about 70% excess weight loss?

Published sleeve gastrectomy cohorts often report mean excess weight loss near 60% to 70% at one to two years. The calculator uses 70% as a representative counseling estimate.

Can I enter height and weight in imperial units?

Yes. Select inches for height and pounds for weight. The calculator converts internally before computing BMI and projections.

Do milestone months reflect exact surgical dates?

Milestones assume average recovery trajectories. Rapid early loss and later plateaus are common, so actual weight at each interval may differ.

Is this a substitute for a bariatric consultation?

No. Surgical candidacy, procedure choice, and expected outcomes require evaluation by a bariatric team including medical, nutritional, and psychological assessment.

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