BMI ≥ 40 kg/m²
Defined as severe (morbid, class III) obesity; under the current 2022 ASMBS/IFSO guideline, assessment for surgery is recommended.
Clinical Calculation Tool
Body Mass Index (BMI) Calculator
Body Mass Index is one of the core clinical indicators for obesity and metabolic surgery decisions. On this page you can compute your BMI and review WHO categories alongside the eligibility thresholds defined by international guidelines (IFSO, ASMBS).
BMI Calculator
Body Mass Index (BMI) Calculator
Enter your height and weight to see your BMI instantly. Discover the clinically accepted range for bariatric and metabolic surgery.
WHO BMI Categories and Clinical Meaning
BMI ranges defined by the World Health Organization (WHO) and their meaning in the context of bariatric surgery.
| Category | BMI Range | Clinical Meaning |
|---|---|---|
| Underweight | < 18.5 | Underweight — nutrition and underlying causes should be evaluated. |
| Normal | 18.5 – 24.9 | Healthy weight range — bariatric surgery is not indicated. |
| Overweight | 25 – 29.9 | Overweight — lifestyle adjustment and clinical follow-up are recommended. |
| Obesity — Class I | 30 – 34.9 | Obesity Class I — surgery may be considered if metabolic comorbidities are present. |
| Obesity — Class II | 35 – 39.9 | Obesity Class II — under current guidance, assessment for surgery is recommended whether or not comorbidities are present. |
| Severe Obesity | ≥ 40 | Severe obesity — clinically accepted range for bariatric surgery. |
Bariatric Surgery Eligibility Thresholds
BMI alone does not determine surgical eligibility; it is evaluated together with the following clinical criteria.
BMI 35–39.9 kg/m²
Under the current 2022 ASMBS/IFSO guideline, assessment for surgery is recommended whether or not an accompanying condition is present. Documenting conditions such as type 2 diabetes, hypertension or sleep apnea strengthens the case.
BMI 30–34.9 kg/m² + Metabolic Disease
Not a range in which surgery is routinely recommended; the current guideline recommends that surgery be assessed in people in this range who have a metabolic disease. The most common example is type 2 diabetes that cannot be controlled despite drug treatment.
Age and General Health
Rather than a fixed upper age limit, overall health and the benefit–risk balance are the deciding factors. Under 18, surgery is considered only in selected cases by a multidisciplinary team; in people over 65, heart, lung and kidney function and fitness for anesthesia are examined in more detail.
Information & Contact
For Information About the Procedures
For detailed information about bariatric and metabolic surgery procedures, you may use the contact channels below. Initial consultations for international patients can be arranged remotely via video call or WhatsApp.
Specialist Surgeon
Assoc. Prof. Dr. Hasan Abuoğlu
Associate Professor of General Surgery
- Office hours
- Weekdays 09:00 – 18:00 (Türkiye time, GMT+3)
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