Bariatric Surgery Weight Loss Tracker
Compare your progress to typical excess weight loss targets after bariatric surgery. The calculator estimates expected loss based on surgery type and time since your procedure.
Progress Snapshot
Pre-op BMI
41.5
Excess weight
47.8 kg
Weight lost
25 kg
% excess weight lost
52.4%
Expected range for 8 months
Typical sleeve patients experience approximately 38–52% excess weight loss at this point. You are tracking within typical expectations following bariatric surgery. Continue follow-up with your care team.
How to Use This Calculator
Confirm surgical timeline
Enter the months since your bariatric surgery to compare against expected milestones. Even small variances are common—use this as a guide, not a diagnosis.
Track with your clinical team
Use the excess weight loss percentage when meeting with your surgeon, dietitian, or support group. They can help interpret deviations and adjust your plan.
Focus on habits, not just numbers
Prioritise protein (60–80 g/day), hydration, vitamin supplementation, and gradual activity progression to sustain healthy weight loss.
Formula
BMI = Weight (kg) ÷ Height (m)²
Ideal weight = 25 × Height (m)²
%EWL = (Weight lost ÷ Excess weight) × 100
- Excess weight = Pre-op weight − Ideal weight.
- Expected EWL ranges derived from ASMBS and bariatric follow-up studies.
- Progress curves assume adherence to post-op nutrition, supplementation, and activity guidelines.
Full Description
Bariatric surgery produces rapid weight loss during the first 12–18 months by reducing stomach capacity and altering gut hormones. This calculator contextualizes your progress against expected excess weight loss ranges published by bariatric associations.
Remember that individual results vary. Factors such as starting BMI, adherence to protein/vitamin protocols, physical activity, and metabolic conditions influence outcomes. Ongoing support from multidisciplinary teams improves weight maintenance and overall health.
Frequently Asked Questions
What if my weight loss stalls?
Plateaus are common around 6–9 months. Review protein intake, hydration, food logging, and activity. Consult your clinic before making major changes.
Can I regain weight after surgery?
Yes. Lifestyle factors, hormonal shifts, and medication changes can impact weight. Regular follow-ups and support groups help mitigate regain.
Why do surgery types have different expectations?
Procedures vary in restriction and malabsorption. Gastric bypass and duodenal switch generally produce higher excess weight loss than sleeve gastrectomy.
Is this calculator a substitute for medical advice?
No. It provides education and benchmarks. Always follow individualized guidance from your bariatric surgeon, dietitian, and primary care team.