Body composition calculations (How to)

[stack_it]

With a quick little search you can find an online calculator for just about anything. Well if you like to do things yourself thenheres how to make some of the basic calculations.

Body mass index (BMI)
- Used to determine whether a person is at a healthy body weight.
- Muscularity can effect accuracy.

How to calculate:

Weight(kg) divided by height(m) squared

1kg = 2.2lbs and 1m = 39.25 inches

I'll use myself as an example. I'm 6' tall 183lbs this morning. So using the conversions above that makes me 1.83 meters and 83.1 kg's.

83.1 divided by 1.83 squared (square your height first) so that makes it 83.1 divided by 3.34. That means my BMI is 24.88

BMI Less than 20 — Under Weight

BMI 20-25 — Normal Weight

BMI 25-30 — Over Weight

BMI 30-40 — Obese

BMI Over 40 — Severely Obese


I fall into the normal range. One thing to keep in mind with bmi is that muscularity plays a big role. As you can see I'm close to being overweight at only 183lbs. That's because I have little fat and decent muscle. So if it say you are overweight it does not mean that you are unhealthy. This is just to make a quick assessment of whether you are at a healthy weight. If you feel you are at a healthy weight and your bmi says otherwise then you should have your body fat percentage measured to be sure.

[stack_it]

Calculating optimal body composition.

Research suggests that a range of 8-22% body fat is optimal for men and 20-35% for women. Obviously most of the men reading this will want to be below 15%. The 22% is a little high IMO but that's mainly for your everyday guy on the street.

In order to do this calculation you need to know your current bf% or atleast a very close estimate. I recommend you have it tested with metal calipers. The electric handheld testers are very inaccurate and the other methods are expensive and hard for the every day lifter to do. Once you know your body fat percentage here's how to calculate your optimal weight in order to get to your optimal bf%

I have right at about 10% bodyfat so I won't use myself for this example. Instead I'll use someone with a higher bf%.

Test subject: Standby 5'11" 212lbs and 16% bodyfat

First calculate what your fat free weight is. Fat free weight Is the amount of total body weight contained in bones, organs, and muscles.

Total body weight - fat weight = fat free weight
In this case we have 100% - 16% = 84%

This means that 84% of total body weight I'd fat free weight. Which means the fat free weight of this person is 178.08lbs (212 x 84%)

Let's say that this person wants to reach 10% bf. The formula to figure out what weight he needs to reach is "fat free weight divided by (1 - optimal % fat) make sure you express the optimal percent as a decimal.

Here's what it would look like.
178.08 divided by (1 - .10) so 178.08 divided by .9
That equals 197.86lbs

So assuming that this person maintains there current muscle mass he would have to drop down to 197.86lbs to reach his 10% bodyfat goal.

When doing this calculation it is best to set goals in increments of 5% and then recalculate once you hit each goal in order to compensate for any muscle mass gained or lost. On average with out the help of aas or thermogenics it should take about 6 weeks to drop 5%. assuming diet and training are correct.

If anyone is confused or unclear about a certain part then let me know and I'll try to explain. Also I apologize for any typos as this was all written from my phone.

[Times Roman]

why don't you just order a caliper and do an "actual" measurement? just don't get the inexpensive plastic type, they don't last very long... probably $25 should get you a fairly good quality item... then a 7 point check employing an "averaging" technique and you will be very close to your true bf%

[stack_it]

why don't you just order a caliper and do an "actual" measurement? just don't get the inexpensive plastic type, they don't last very long... probably $25 should get you a fairly good quality item... then a 7 point check employing an "averaging" technique and you will be very close to your true bf%

That's what I suggested. The calculation for bf is to determine the weight you need to get to in order to reach your goal body fat percentage. It does not calculate your current bf%.

The bmi calculator up top is more for people who have just began working out or don't work out and would like to know if they are sitting at a healthy weight.

[BigBuck6]

31.37 haha I love being "obese." You gotta love BMI!

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31.37 haha I love being "obese." You gotta love BMI!

Haha yea bmi doesn't really pertain to bodybuilders lol. I put it in there more for the new members that have just started exercising and dieting.

[Times Roman]

I went to the dr. over a year ago, 6' and almost 1"... I was a very very lean 215, and doc whips out the BMI chart and says i need to be down around 175??? wtf????

you know how much lbm I'd have to lose? wtf is the point?

so i just laughed at his dumb asss... those charts were never meant to be used at an individual level, more of a statistical tool, yet pulls it out he does.... what a dumb asss

[stack_it]

I went to the dr. over a year ago, 6' and almost 1"... I was a very very lean 215, and doc whips out the BMI chart and says i need to be down around 175??? wtf????

you know how much lbm I'd have to lose? wtf is the point?

so i just laughed at his dumb asss... those charts were never meant to be used at an individual level, more of a statistical tool, yet pulls it out he does.... what a dumb asss

I'd have sat and tried to debate with my doc on why he shouldn't follow that chart lol. I was hesitant to post the bmi calculator for just this reason but like I said it's for the new inexperienced members with little to no muscle mass. Bodyfat % is always better to use.

[Standby]

so ill continue to try and drop to 200 then we can do this fun math again lol

[BigBuck6]

Haha yea bmi doesn't really pertain to bodybuilders lol. I put it in there more for the new members that have just started exercising and dieting.

I understand and appreciate it it's been a while since I have actually seen the calculations done and instructions on how to do them.