BMI measures an individual's total body fat content.

More Info: The body mass index is correlates a person's height to weight, which for adults has demonstrated to have a strong connection to total body fat.

How to Calculate Your BMI

There are plenty of online BMI calculators that can measure your BMI instantly, but you can also calculate the measurement yourself.  Simply take your metric weight (kg) and divide it by your height (m) squared. 

Metric Example: weight (kg)/[height (m)]²=BMI

68kg/[1.78m]²=

69/3.168= 21.78 healthy weight

To convert inches and pounds to their metric equivalents, simply take your weight in pounds, divide it by your height in inches squared, then multiply the solution by 703

US Unit Example: weight (lbs)/[height (in)]² x 703=BMI

150 lbs./[70 in. ]²=

150/4900= .0306 x 703= 21.5 healthy weight

Body Mass Index Limitations

Though it can't be disputed that the body mass index is a very simple tool that can help to indicate a weight problem, there is no doubt that it has its limitations.  The index does not differentiate between fat and muscle.  For the average person this factor is generally not an issue and the index is fairly accurate but for athletes the body mass index may be quite inaccurate.  It also does not take into consideration sex categorizing men and women together even though men inherently have more muscle mass than women.   Yet another factor that may cause the results to be skewed is that it does not take into consideration natural aging and the fact that as you age you tend to lose more muscle.

Ironically, the body mass index does not take into consideration the differences in body fat between boys and girls as well as differences in body fat as they age.