T Nation

How does one measure body fat percentage

How does everyone know their bodyfat percentage? This doesn’t seem like a very precise science. Can you guess?

I have and always will think that anyone that states, “I am 215, 6’5” w/8.275% BF" is fooling themselves. Use the mirror, your training diary and how your clothes fit as your gauge. But, “I am 5’10” now and am at 14.275% BF and want to get to 11.3185% in 4 weeks, can anyone recommend a training routine and a diet, I have a food scale that weighs food to the 1/1000 of a gram, and can document my basal metabolic rate to the nearest .01%, can you help?" Let the nonsense go

If you don’t want to pay to have one of those impedance tests where they plug you into the mains and a laptop, or take a dip in a water displacement tank. You have another option apart from a skin fold test. WARNING this is a very rough guestimate I found a few years ago on the www. You will need a calculator and a measuring tape in inches.

Bodyfat = (-98.42 + (4.15 x waist (inches)) - (.082 * bodyweight (pounds)).

Ok heres an example just in case your fat fast has really kicked in!

Say you weigh 200 lbs and your waist is 38 inches:

-98.42 + 4.15 x 38 = 59.28 then
.082*200 = 16.4
So subtract 16.4 from 59.28 = 42.88

If you don’t have a headache then do this final calculation

% Bodyfat = Bodyfat (the number you got above) divided by body weight in pounds so for this example % Bodyfat = 42.88/200 *100 = 21%

I have found for myself that its probably within +/- 5 % of an impedance test, but I would be interested to know if it is actually worth using as a bodyfat guestimator. So get brave and crunch the numbers.

Of course this final test may give you a very rough idea of % body fat.

Greenpeace try and put you back into the sea when you go to the beach (15%)

Women try and take you back to their place when you go to the beach (10%)

Women take you back to their place whenever(5%)

Don’t disagree with what’s been said…just some “fine tuning”:


1)The Anthropologic Calculations like Kiwi gave are great estimates, but become VERY inaccurate at high bodyfat percentages (rougly greater than 29-30%) AND are dependant upon how you genetically deposit fat stores.(eg; if you tend to store more fat in the chest and face area, these become less accurate). But all in all; good formulaes.


2)I use two impedence monitors (Tanita and Omron)to guage RELATIVE progress. Our own vanity can sometimes make “looking in the mirror” THE most inacurate guage. However…that is the “final” guage, huh? “How We Look Nekkid”…(I think TC should be nominated for the Nobel in Literature (or something!) for giving the world that rallying cry!)

At what range of bodyfat should ones Abs be fully visable?

According to that mathematical formula I’m at 8%. I never would have guessed I was that low, because I’m not satisfied with my ab development.

Of course this is making me worry… if I’m not satisfied, at what number will I be? haha.

I remember a long time ago that Dan Duchaine was not interested in your body fat percentage when it came down to whether or not your abs showed. So get some skinfold calipers and take a vertical fold about an inch to the side of the belly buttom. If its a single digit then you’ll most likely be able to see your abs. If not then you’ve got to work harder. By the way, all body comp methods have serious problems when it comes to accuracy. I can describe later as I’m in the middle of describing these problems in my thesis project. Most methods are fairly reliable though, so you can use them to look at changes. Tanita scales and accumeasure calipers are pretty good and reasonably inexpensive.

The most accurate method is post mortem measurement, I’m not up for that. My method is pretty popular…I just make something up that makes me sound buff. 8-10% is realistic enough and if people aren’t very well informed in that area they’ll believe it.

Thanks Jason. I’d be interested in reading your thesis when you’re done with it. If that’s ok, an all.