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BMI = Kg / (m)2

For those used to American measures:

Divide your height (in inches) by 39.36
to determine your height in meters.

Divide your weight (in pounds) by 2.2
to find determine your weight in kilograms.

The final result is your BMI.

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The American Institute for Cancer Research considers a BMI between 18.5 and 25 to be an ideal target for a healthy individual (though many sources consider a BMI of less than 20 to be underweight). If a BMI is 25 or above, the person is considered overweight. above 30 is considered obese. Note that the BMI scale may improperly consider some people overweight or obese due to it's inability to distinguish between fat weight and muscle weight. its an inaccurate indicator of actual health.

TLA for Broadcast Music, Inc. BMI represents music performers and collects royalties from businesses which use represented artists' music for distribution to said artists. They are a smaller organization than ASCAP, but larger than SESAC.

Something I do not get. Why the complicated instructions for users of inferior units? It's not like the numbers 18.5, 20 and 25 have some intrinsic meaning; they're just the way these ratios come out when you have height in metres and weight in kilgrams. And every time you see the BMI in English-language press, they always use metric constants and tell you how to apply the conversions.

So the logical thing to do would be to tell Yanks to do it all with lbs and inches, and convert the 3 magic numbers once and for all. In fact, I have performed this unique feat.

Between 0.026 and 0.028
possibly underweight
Between 0.028 and 0.036
just right
Between 0.036 and 0.043
overweight
Above 0.043
obese
There! That wasn't so bad, was it?

Of course, people stick with this triple-conversion mania for much the same reasons that they stick to a measuring system based on the width of some king's nose -- a mantic awe of numbers.

1. Largest competitor to ASCAP.

2. A 6502 instruction that performs a branch if the S flag is set (i.e. the last operation returned a result whose most significant bit is 1).

• Function: If(S) PC + N => PC
• Opcode number: \$30

As opposed to: BPL

Body Mass Index, a measure of human skinnyness or obesity. It is a way to measure if you are overweight or underweight.

Underweight: BMI of less than 18.5
Normal 18.5 - 24.9
Overweight 25.0 - 29.9
Obesity 30.0 - 39.9
Extreme Obesity 40.0 and greater

Just where to draw the line between normal and overweight is a judgement call. There are slight increases in risks of diabetes and heart disease with BMIs over 22. These risks become dramatically larger with BMIs over 30.

As noted over at ideal body weight, the following formula is an estimate that works for 90% of adults, but not for athletes, the aged or adolescents under 20 years of age. f you carry a lot of muscle then BMI won't work for you. If you think that you fall outside this formula's competence, then use a more accurate measurement technique to ascertain how much body fat you carry.

Formula: `BMI = w / (h * h)`, where w is weight in kilograms, and h is height in meters.
Or a version with the conversion from imperial units built in:
`BMI = w * 704.5 / (h * h)`, where w is weight in pounds and h is height in inches.

Worked example for my BMI:
I am 1.80m tall (just under six foot)
I weigh 72kg (147 pounds)
My BMI = 72 / (1.8 * 1.8) = 22.22

So now that I know that I am within the ideal weight range, how big is my range? Rearranging the equation for weight gives:
`w = BMI * h * h`
The ends of the ideal weight range correspond to a BMI of 18.5 and 25.0. Given my height, this gives
Low: w = 18.5 * 1.8 * 1.8 = 59.94 kg (131.9 pounds)
High: w = 25 * 1.8 * 1.8 = 81 kg (178 pounds)
Note that this calculation seems to be quite sensitive to small changes in height (using a height of 1.805 m instead yields a minimum weight of 60.27kg) so try to get that accurate.
Given that the input numbers of height and weight are only accurate to two digits, the output probably has the same degree of accuracy. Thus my ideal weight range is 60 to 81 kg.

Sources: Sites that Google turned up and the source code of their javascript BMI calculators. All calculations were tested in Excel

Though the above noders are correct in their definition of Body Mass Index, they are incorrect about its applicability. Body Mass Index is NOT an accurate measure of a person's "fatness".

First, a bit of history. The Body Mass Index scale is the brainchild of a Belgian mathemetician named Lambert Adolphe Jacques Quetelet. He was NOT a physician. Mr. Quetelet first released this formula in the 1800's as a quick way to measure the relative fatness of the population and thus allow the government to allocate resources appropriately. The formula is based off of Quentelet's idea of an "average man". Although averages are fine when used to measure populations, measuring against an average is seldom a good idea for individuals. In fact, Quetelet himself even said BMI could not and should not be used to measure the level of fatness of an individual. Body Mass Index is a fundamentally flawed system of measure and has no place in modern medicine. Our continued reliance on such an inadequate measuring system is detrimental to the health of our society, as well as our economy.

BMI is anatomically and logically wrong. Physiologically speaking, there is no reason to divide someone's weight over the square of their height. Quetelet essentially reverse engineered this formula; thus if a person is fat, they will have a high BMI. However, having a high BMI definitely does not mean a person is fat. This is because BMI only accounts for height and weight. It does not account for several other variables involved in calculating "fatness", most notably bone density and muscle mass, i.e people that have strong bones and well toned muscles will be classified as overweight or obese, though they may not be. Relative shoulder width and body girth are two of several other factors that should be taken into account when measuring the fatness of an individual.

Most importantly, the Body Mass Index scale creates distinct definitions of "Underweight", "Overweight", and "Obese". This is complete garbage, because every individual is just that, an INDIVIDUAL! You can't judge if someone is underweight, overweight or obese based on the weight of the "average" person of their height. Just because someone is not "average" doesn't mean they are unhealthy, fat, or even underweight!

A continued reliance on such a flawed system to measure the fatness of individual people is undoubtedly wrong. People rely on their doctors to keep them healthy; if the doctors are in turn relying on an inaccurate tool, they are being unfair to their patients. The harmful effects of using such a scale are numerous. First off, the mental health of the population may be adversely affected. Our society already hears enough about how we don't look exactly like the cracked-out runway models and anorexic celebrities we see on TV every day.

Secondly, because doctors are constantly telling their patients they're overweight, fad diets have become a billion dollar industry. People are subjecting themselves to the potential kidney damage caused by "the Atkins diet" and other no-carb diets, not to mention the countless other severe deficiencies and problems with fad diets and weight loss products, all in the name of caring for their "health". Is this really health we are chasing, or acceptance?

Finally, health insurance companies (at least here in America) have the right to increase their premiums for people with high BMI's. Regular, healthy individuals are being charged more, even in our jobless economy, just because they have strong bones or toned muscles. Am I the only one who thinks this is ridiculous?

It's high time modern medicine introduced a new, more accurate system of measuring obesity, because this one is clearly broken.