BMI & surgery eligibility calculator

Enter your height and weight to get your BMI, understand where you sit on the surgical eligibility scale, and hear what Barry thinks about your situation. Works in metric or imperial.

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15 18.5 25 30 35 40 55+
Surgery eligibility guide
Gastric band
BMI 30–35 with conditions, or 35+
Adjustable, reversible. Slower weight loss. Less common now.
Enter BMI
✂️
Sleeve gastrectomy
BMI 35–50 typically
Stomach reduced to a sleeve. Permanent, no malabsorption.
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↪️
Gastric bypass
BMI 35+ (40+ without conditions)
Gold standard for T2 diabetes. Greater loss, more vitamins needed.
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🔄
Duodenal switch
BMI 50+ typically
Most powerful option. Lifelong commitment to vitamins.
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BMI is one eligibility factor. Clinicians also assess comorbidities (type 2 diabetes, sleep apnoea, hypertension), previous weight loss attempts, and psychological readiness. These results are a guide only. Always discuss with your bariatric team. NHS eligibility thresholds are used above; private thresholds may differ.