Calculating your BMI is very simple, here’s BMI calculation formula for english and metric units:

**English BMI Formula**

BMI = ( Weight in Pounds / ( Height in inches x Height in inches ) ) x 703

**Metric BMI Formula**

BMI = ( Weight in Kilograms / ( Height in Meters x Height in Meters ) )

To calculate your BMI, divide your weight in pounds by your height in inches squared, then multiply the results by a conversion factor of 703. For someone who is 5 feet 9Â inches tall (69 inches) and weighs 180 pounds, the calculation would look like this: [180 Ã· (69)^{2}] x 703 = 26.57.

**What Does The Result Mean?**

Ideal BMI is considered between 18.5 and 25. If you have a BMI lower than 18.5, you are considered by the BMI calculation to be underweight. Anything over 25 is considered overweight, anything over 30 is considered obese, and over 40 is considered morbidly obese.

**Things to Consider:**

Although BMI can be used to measure body mass index for men, women and children, it does have some limits:

- It may underestimate body fat for persons who have lost muscle, such as old persons
- It may overestimate body fat muscular body types, such as athletes