I thought Body Mass Index (BMI) had something to do with your overall density and that to calculate it you had to float in a tank of water or something and then compare the displacement to your weight.
But there are web-based BMI calculators all over the place, asking only that you enter your height and weight, and they give back your BMI.
Are they a farce or are they real? This seems the same as just looking it up on a chart. (Not that it really matters, but I am curious about it.)
You’re thinking of body fat testing by water displacement. Totally different.
Yeah BMI is just a ratio of height to weight. Doesn’t even depend on gender. The only time BMI doesn’t reflect a person’s fitness accurately is if they are extremely muscular (like on the level of being a bodybuilder muscular)… but for the vast majority of the population it’s a pretty good reference point for fitness. What you are thinking of is body fat %, which is what you would want to measure if you were one of the aforementioned very muscular people to get a better sense of how much of your weight is muscle vs. body fat.
body MASS index, so density nor volume are really points of concern.
and while gender isn’t involved directly, there are different scales for men and women.
you don’t even need an online calculator. the formula is deviously simple - it’s your weight in Kg divided by the square of your height in meters.
in pounds and inches, it’s weight/(height^2) times a conversion factor of 703.
Yes, the BMI is a simple equation - any person’s body weight divided by the square of their height. It doesn’t tell you much about bone density, lean mass, or body fat percentage.
So, since the question itself is answered, I’d like to add on a similar one: What’s the deal with those devices that say they are BMI calculators, but, after you enter the height and weight information, require you to hold the device out in front of you for a 30 seconds and shake your body?
They must be doing something, because I get a lower BMI than if I just do the calculation manually.
Is it also just a body fat index or something?
Juh? Do you mean one of these? This device doesn’t need to be shaken, but it’s the closest to what you’re describing that my Google-fu has allowed me to find. I’ve never heard of such a thing.
That was my guess as well; a hand held body fat resistance analyzer. BMI is just weight and height.
While it works in broad terms I’d say that it’s a very effective tool for someone who is any sort of athlete. I will never be in the “proper” range for BMI but I’m in the best shape of my life, training to run a marathon right now. It’s not that BMI isn’t accurate for bodybuilders, it’s not a helpful diagnostic tool for anyone who is significantly athletic, IMO.