bmi

you shouldnt trust bmi though,if you take some athletes and look at their BMI then their overweight,which i doubt is true,ill use kobe bryant for an example
6'6,225 lbs. BMI is 26 and i wouldnt call most athletes overweight,but i might be wrong that might just be in general not counting muscle and all that.i wouldnt use BMI though to determine if i was overweight or ideal.

Well it mostly takes into account that your weight, the majority is fat, and not muscle mass. Whereas most athletes are dead on healthy, so try not to use them as a comparison.

Most people arn't professional atheletes, so the BMI isn't that bad, although it's a pretty simple calculation, don't use it to that great of extent, it's just a guideline.

Yes, it is just a guideline, but being seriously into the overweight categories is bad for other body systems, like your heart, even if it's muscle.

A very vague guideline, it also doesn't take into account things like body structure or bone density or anything else that isn't height or weight.

Exactly; if you go to a good BMI site, it will show how both an elite athlete and a couch potato can have the same BMI, and that other factors should be taken into account.