How is BMI Calculated?

For men and women over the age of 18, your body mass index is calculated based on your current height and weight using a basic formula. This can be done using kilograms and centimeters or using pounds and inches, using one of the following two equations. 

• weight (kg) / [height (m)]2
• weight (lb) / [height (in)]2 x 703

You can also easily determine your weight in kilograms by taking your weight in pounds and diving by 2.2 and multiplying your height in inches by 0.0254 to get your height in meters.  

Your BMI index or score represents the proportion of your weight to your height and provides you a single numerical output that can be used to see where you fall on the BMI chart.

BMI Calculator Chart

For adults, the BMI formula does not consider your age or your gender and the same equation can be used for everyone. Thus, a healthy BMI for men would fall into the 18.5 to 24.9 range, and a healthy BMI for women would look similar. 

The adult BMI categories are as follows:

Learn More About BMI

Knowing your BMI is important because of how widely used this measurement is in epidemiological and pathological studies, as well as how this translates into disease control and prevention. 

While BMI is not a perfect assessment of body fat percentage, a large body of research has associated a high body mass index with a wide array of health problems typically associated with obesity, such as high blood pressure, heart disease, and diabetes. Additionally, because is simple to use, affordable at large scale, and an effective assessment of population health, many healthcare professionals recognize that reducing BMI could result in saving lives.  

Learn more about why BMI is a valuable tool and how you can get your body mass index into a healthy range.