Body Mass Index (BMI) Calculator

What is BMI?

If you are considering bariatric surgery, you should first understand what determines a healthy weight. It's more than just a number on your scale.

Body Mass Index (BMI) is:

  • A number calculated from a person's weight and height.
  • A fairly reliable indicator of whether you’re at an appropriate weight for your height by estimating your body fat.
  • An inexpensive and easy-to-perform method of screening for weight categories that may lead to health problems.

To calculate your BMI, your height and weight are entered into a mathematical equation and the resulting number reveals whether you’re underweight, normal weight, overweight, or obese. If your BMI is 25 or above — and you are not an athlete or you don’t have a muscular build — you could be at risk for numerous health conditions, and might be a candidate for bariatric surgery.

Calculate your BMI now.

How is BMI Calculated?

BMI is calculated the same way for both adults and children.

The calculation is based on the following formulas:

​Measurement Units​ Formula and Calculation
​Pounds and inches ​Formula: weight (lbs.) / [height (in)]2 x 703

Calculate BMI by dividing weight in pounds (lbs.) by height in inches (in) squared and multiplying by a conversion factor of 703.

Example: Weight = 150 lbs, Height = 5'5" (65")
Calculation: [150 ÷ (65)2] x 703 = 24.96

​Kilograms and meters (or centimeters) ​

Formula: weight (kg) / [height (m)]2

With the metric system, the formula for BMI is weight in kilograms divided by height in meters squared. Since height is commonly measured in centimeters, divide height in centimeters by 100 to obtain height in meters.

Example: Weight = 68 kg, Height = 165 cm (1.65 m)
Calculation: 68 ÷ (1.65)2 = 24.98

Source: Centers for Disease Control and Prevention

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