BMI Calculator for Weight Loss Surgery Patients

Calculate your Body Mass Index and understand how it relates to weight loss surgery eligibility and goals.

Enter your height in inches (e.g., 70 for 5'10")
Enter your weight in pounds
Enter your age in years

How to Use This Calculator

  1. Enter your height in inches (e.g., 70 for 5'10")
  2. Enter your current weight in pounds
  3. Provide your age and gender for more personalized information
  4. Click Calculate to see your BMI and how it relates to weight loss surgery

Formula Used

BMI = (Weight in pounds / (Height in inches × Height in inches)) × 703

Where:

  • Weight = Your current weight in pounds
  • Height = Your height in inches
  • 703 = Conversion factor for imperial units

Example Calculation

Real-World Scenario:

A patient considering bariatric surgery wants to understand their current BMI and eligibility

Given:

  • Height = 66 inches (5'6")
  • Weight = 250 pounds
  • Age = 42 years

Calculation:

BMI = (250 / (66 × 66)) × 703 = 40.3

Result: The patient has a BMI of 40.3, which falls into the "Obese Class III" category and meets the criteria for bariatric surgery without comorbidities.

Why This Calculation Matters

Practical Applications

  • Determining eligibility for weight loss surgery
  • Setting realistic post-surgery weight goals
  • Tracking progress after bariatric procedures

Key Benefits

  • Provides objective measure of surgical candidacy
  • Helps set achievable weight loss targets
  • Quantifies health risks associated with excess weight

Common Mistakes & Tips

Make sure to enter your height in inches, not feet and inches. For example, if you're 5'10", enter 70 (5×12 + 10), not 5.10. Even small errors in height can significantly affect your BMI calculation.

BMI doesn't distinguish between muscle and fat. Athletes or those with high muscle mass may have a high BMI despite having low body fat. Discuss with your healthcare provider if you have concerns about your BMI interpretation.

Frequently Asked Questions

Most insurance providers and surgeons require a BMI of 40 or higher, or a BMI of 35-39.9 with at least one obesity-related health condition (like type 2 diabetes, hypertension, or sleep apnea). Some newer procedures may be approved for patients with lower BMIs.

Weight loss varies by procedure and individual. On average, patients lose 60-80% of their excess weight after gastric bypass, 50-70% after sleeve gastrectomy, and 40-50% after gastric banding. Excess weight is the difference between your current weight and your ideal weight for a BMI of 25.

No, BMI is just one factor. Surgeons also consider your overall health, previous weight loss attempts, psychological readiness, commitment to lifestyle changes, and specific medical conditions. A comprehensive evaluation is necessary to determine if you're a good candidate for surgery.

References & Disclaimer

Medical Disclaimer

This BMI calculator is for informational purposes only and is not a substitute for professional medical advice. Always consult with a qualified healthcare provider before making any decisions about weight loss surgery or treatment plans.

References

Accuracy Notice

BMI is a screening tool and does not directly measure body fat or health. Athletes and individuals with high muscle mass may have a high BMI despite low body fat. Other factors such as age, ethnicity, and distribution of fat also affect health risks. Discuss your results with a healthcare professional for personalized advice.

About the Author

Kumaravel Madhavan

Web developer and data researcher creating accurate, easy-to-use calculators across health, finance, education, and construction and more. Works with subject-matter experts to ensure formulas meet trusted standards like WHO, NIH, and ISO.

Connect with LinkedIn

Tags:

health medical-clinical-calculators bmi weight loss surgery patients medical