Know Your Number. Take Control of Your Health.

BMI Calculator for Bariatric Surgery Candidates

Body Mass Index (BMI) is a simple tool used to estimate body fat based on height and weight. It’s an important first step in determining whether you may qualify for weight-loss surgery at the BASS Bariatric Surgery Center.

Adult BMI Calculator

Units
Height
Weight
Your BMI: 0.0
Weight Status: -

BMI is a screening measure and does not diagnose health.

What Is BMI and Why Does It Matter?

BMI is a mathematical formula:

weight (lbs) ÷ height² (inches) × 703‍

It provides a quick way to classify your weight status:

  • Underweight: BMI < 18.5
  • Normal weight: BMI 18.5–24.9
  • Overweight: BMI 25–29.9
  • Obesity Class I: BMI 30–34.9
  • Obesity Class II: BMI 35–39.9
  • Obesity Class III: BMI ≥ 40

A BMI of 35 or higher may indicate that you qualify for bariatric surgery, especially if you also have health conditions related to obesity.

Adult Body Mass Index (BMI) chart from University of Vermont AHEC (circa March 2007). Displays height along the top—ranging from 5'0″ to 6'4″—and weight along the bottom, from approximately 95 to 245 pounds. Each intersecting cell shows the corresponding BMI value. Includes a note recommending weight loss for individuals with BMI ≥ 30, and for those with BMI between 25 and 29.9 who have elevated waist circumference or other risk factors; for others in that range, it suggests preventing further gain.
Tap to open full-size chart.

Health Risks of a High BMI

According to the CDC, over one-third of U.S. adults are obese — and obesity increases the risk for many chronic health conditions, including:

  • Type 2 Diabetes
  • Heart Disease
  • High Blood Pressure
  • Sleep Apnea
  • Osteoarthritis
  • GERD (acid reflux)
  • Fatty Liver Disease
  • Depression

Is BMI Always Accurate?

While BMI is a helpful screening tool, it isn’t perfect. It doesn’t distinguish between fat and muscle. That means:

  • Athletes may have a high BMI due to muscle, not fat.
  • Older adults may have a normal BMI but still carry excess fat.

That’s why we also recommend tracking waist circumference for a more complete picture.

How to Measure Waist Circumference

  1. Place a tape measure above your hip bones.
  2. Make sure it’s level and snug — but not tight.
  3. Measure after exhaling naturally.

High abdominal fat increases the risk for heart disease and diabetes, even in people with a normal BMI.

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Are You a Candidate for Bariatric Surgery?

You may qualify for bariatric surgery if you:

  • Have a BMI of 40 or higher, or
  • Have a BMI of 35+ with obesity-related health issues
  • Are 100 pounds or more over your ideal body weight
  • Have been unable to lose weight through diet and exercise
  • Are between the ages of 14 and 75

If weight gain is due to a temporary condition (like pregnancy), you may not be eligible.

Why Choose Surgery Over Diets or Injections?

Bariatric surgery is a proven long-term solution. Our experienced team offers:

  • Gastric Sleeve
  • Gastric Bypass
  • Duodenal Switch
  • Adjustable Gastric Band

These procedures can eliminate or improve diabetes, high blood pressure, sleep apnea, and more — all while helping you regain confidence and mobility.

We do not recommend or prescribe weight-loss injections like semaglutide due to safety concerns.

Start Your Journey Today

Request a Bariatric Consultation with one of our expert bariatric surgeons in Walnut Creek or Brentwood.