Here's a new BMI calculation, and some background on it. It doesn't do away with BMI's poor ability to distinguish between fat and muscle, but it does fix some error at the extremes. The classic BMI, as the new BMI's originator Nick Trefethen says, has "millions of short people think[ing] they are thinner than they are, and millions of tall people think[ing] they are fatter."
You'll have to scroll down past the photo of Brad Pitt.
Below is a calculation for where your BMI ranks, both within your country and globally. It will tell you which country has the most people like you (people of your sex, age, and BMI).