Body Mass Index - BMI
Yet another way of approximating body composition for use in large-scale medical studies and for health reports to refer to in the popular press. This particular measure is calculated by dividing your mass in kilograms by the square of your height in meters. While such simplistic measures are useful for large statistical samples of the general population, their value is highly limited for individuals, particularly athletes who can be very healthy and have low bodyfat percentages despite having a higher-than-recommended BMI.
a web-based BMI calculator, bodyfat estimator, and other tools may be found at Phys' health calculator page