BMI is not always useful...

When using a BMI calulator, a BMI of 18.50 or lower is considered under weight. A BMI of 18.50 to 25.00 is considered normal. A BMI from 25.00 to 30.00 is considered overweight. Finally, a BMI over 30 is considered obese.

BMI: Body Max Index. Pretty much a way to calulate if you're over, normal or under weight. If you're underweight on the BMI scale, that's bad no matter what. Eat some food and lift some weights. Where the BMI calulator becomes in accurate is when it says you're overweight. Why? Because it used weight and height... not fat percentage. Fat percentage is a much better way to tell if someone is overweight, because it literally tells you how much of your body is made up of fat.

Incase you do not believe me when I say the BMI is in accurate, let me give you an example: I weigh 168-169 now. I am 5 feet 8 inches. My BMI is 25.62... Which is considered overweight. I can see my abs, crank out around 20 pull ups and dead lift double my body weight. As you can see, I am not overweight... but my BMI tells me I am.

So if you're a muscular, lean girl or guy, stop using the BMI calulator. It's not useful to you.