Maybe the whole Body Mass Index (BMI) thing just isn't too accurate. I mean, how can a tool that takes into account only my height and weight really tell me if I'm overweight or not? What about muscle mass -- not that I have too much -- and bone density, and body fat? Don't all these factors play a role in what number appears on my bathroom scale? Surely, they do. Still, BMI measurements serve as a general guide, offering somewhat of a clue about weightiness.

Runner's World offers this cool BMI calculator you might want to check out. It's really easy to use. Just enter your weight (mine is 135) and your height (I'm 5'7") and presto! Your BMI number will present itself in an instant. Mine is 21.1, which means I am in a normal weight range. Here's how the numbers break down, according to the National Institutes of Health.

• Underweight: Less than 18.5

• Normal Weight: 18.5 to 24.9

• Overweight: 25 to 29.9

• Obese: 30 or greater
  
  

For more about Body Mass Index, check out this site. And for a different spin on BMI, use this AOL Body tool. It even includes waist measurement as an indicator.