The Body Mass Index (BMI) Calculator can be used to calculate BMI value and corresponding weight status while taking age into consideration. Use both the “Metric Units” for the International System and Imperial Units for the US. Note that the calculator also computes the Ponderal Index in addition to BMI. BMI is a measurement of a person’s leanness or corpulence based on their height and weight, and is intended to quantify tissue mass. Although BMI has limitations in that it is an estimate that cannot take body composition into account, it can be used as a general indicator of a healthy body weight based on a person’s height. The value obtained from the calculation of BMI is widely used to categorize whether a person is underweight, normal weight, overweight, or obese depending on what range the value falls between.