To use a body fat calculator, such as the body mass index (BMI), enter height and weight into the calculator and click on "calculate," states the National Heart, Lung, and Blood Institute (NHLBI). Compare the results to the chart provided to determine the BMI category and learn more about any risks associated with the BMI results. The BMI can be used as a screening tool to assess a person's risk for certain health conditions.
The BMI does not directly measure body fat, but has been shown to be correlated with direct body fat measurements, such as skinfold thickness measurements, notes the United States Centers for Disease Control and Prevention. It is inexpensive and easy to calculate using the steps below.
- Go to a health website
- Enter the height
- Enter the weight
- Calculate the BMI
Visit a health website such as the NHLBI. Click on "Public," then "Education and Awareness." Choose "Aim for a Healthy Weight" and then click on "BMI Calculator."
Enter the height in feet and inches. If the metric system is preferred, enter the height in centimeters.
Enter the weight, in pounds, as a whole number. Enter the weight in kilograms if the metric system is preferred.
Click on "Compute BMI" to calculate the BMI. Compare results to the category list. A BMI result less than 18.5 is considered underweight, while a BMI that is at lest 30 is considered obese. If the BMI falls between 18.5 and 24.9, it is considered normal, while a BMI between 25 and 29.9 is considered overweight, notes NHLBI.