What is the difference between Body Mass Index (BMI) and Body Fat Percentages?

How is each calculated? Which is more useful? accurate?

Public Comments

1. BMI is a general indicator of fat in a person's body. It takes your height vs. your weight, does a quick equation, and gives a rough estimation of your body fat. It's highly inaccurate and does not take into account highly muscled people. For example, I'm 5'7, 155 lbs, and I'm overweight on the scale. I run marathons, play sports, practice kung fu, and I am physically fit, so it's wrong. Body Fat % is simply the percentage of weight of your body that is from fat. It can be found from a caliper test, and electrode test, or a fully body submersion test.