Body Mass Index or BMI Calculator Online

The Body Mass Index (BMI) Calculator can be used to calculate BMI value and corresponding weight status while taking age into consideration. Use the "Metric Units" tab for the International System of Units or the "Other Units" tab to convert units into either US or metric units. Note that the calculator also computes the Ponderal Index in addition to BMI, both of which are discussed below in detail.

Reference

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. These ranges of BMI vary based on factors such as region and age, and are sometimes further divided into subcategories such as severely underweight or very severely obese. As previously mentioned however, due to a wide variety of body types as well as distribution of muscle, bone mass, and fat, BMI should be considered along with other measurements rather than being used as the sole method for determining a person's "healthy" body weight.

Body Mass Index Formula

Below are the equations used for calculating BMI in the International System of Units (SI) and the US customary system (USC) using a 5'10", 160-pound individual as an example:

USC Units: BMI = 703× mass (lbs) height2 (in)  = 703× 160 702  = 22.96 kg m2 SI, Metric Units: BMI =  mass (kg) height2 (m)  =  72.57 1.782  = 22.90 kg m2

Ponderal Index

The Ponderal Index (PI) is similar to BMI in that it measures the leanness or corpulence of a person based on their height and weight. The main difference between the PI and BMI is the cubing rather than squaring of the height in the formula (provided below). While BMI can be a useful tool when considering large populations, it is not reliable for determining leanness or corpulence in individuals. Although the PI suffers from similar considerations, the PI is more reliable for use with very tall or short individuals, while BMI tends to record uncharacteristically high or low body fat levels for those on the extreme ends of the height and weight spectrum. Below is the equation for computing the PI of an individual using USC, again using a 5'10", 160-pound individual as an example:

USC Units: PI =  height (in) ∛mass (lbs)  =  70 ∛160  = 12.89 in ∛lbs SI, Metric Units: PI =  mass (kg) height3 (m)  =  72.57 1.783  = 12.87 kg m3

 aa Adult BMI calculator based on 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and The Obesity Society. BMI classification. World Health Organization. Adapted by Mayo Foundation for Medical Education and Research. Child BMI calculator based on clinical growth charts. Centers for Disease Control and Prevention. Adapted by Mayo Foundation for Medical Education and Research. Privacy assurance: Information that you enter won't be saved or sent to any website.