Establishing body fat percentage a different way?

Last night I found a link on CC to a website where you can determine your body fat percentage using some online calculations determined after entering age, height, weight, sex, and some body measurements. Is this a reliable method? I have a scale that calculates my body fat percentage much higher than when I use the following link:

http://www.healthcentral.com/cholesterol/home -body-fat-test-2774-143.html

 Admittedly, I'm much more happy with the above calculations.

I'd love to hear what some of you think!

Thanks!

Unfortunately I don't have a tape measurer, or I would have done it.

 

Definately saving the link though! Thanks,

i tried it and it came out within 2% of what my body fat scale tells me.

neigher websites or scales are reliable measures of body fat.

but they are useful for comparison purposes. 

according to my inaccurate scale, i have lowered my body fat by about 15% in two years.  and gained significant muscle.  this is perfectly consistent with my fitness level, my weight, and the fit of my clothes.  whether the numbers are perfectly accurate is irrelevant to the fact that it is a good guage of health.

Original Post by pgeorgian:

i tried it and it came out within 2% of what my body fat scale tells me.

Hmmm...my scale says my body fat percentage is about 11% more than what that website says (24.1% vs. 35% or worse depending on the time of day). I'm more inclined to believe the site because a) it's just so much nicer that way! and b) I have quite a strong, muscular body. But I do have my layer of chub, though, so who knows?!

My Tanita scale is never accurate on body fat percent UNLESS I check it about 3 hours AFTER a meal and for some reason, right before dinner seems to be most accurate.  I used a caliper and then got on the scale and it was within .3% on average checking it over a period of weeks...anything in the morning shortly after I got up read very high on the scale compared to calipers and is completely unreliable.

I read somewhere that hydration level could affect the electric impedence tests like scales use to determine body fat percentage, so it would make sense that in the morning, when you are the least hydrated, it would give you the least accurate results.  Later in the day, when you should normally be better hydrated, it would give a better result, which may account for what citidel1980 described. 

For the person who started this thread, if you are not hydrating yourself properly by drinking sufficient amounts of water, it might explain the big difference in the calculated number on the website and your scale.

Hmmm....I take diuretics and I wonder if that screws with my Tanita readings...anyone have input?

From the website you linked

Your Results

You have 21% body fat.

You have 57.5 Pounds of fat and 216.5 Pounds of lean (muscle, bone, body water).

 

From wikipedia

Another well-known method using height and circumference is the YMCA formula. It uses only body weight in pounds, and waist in inches (at navel), to calculate body fat percentage using the formula (for women):

The formula for men substitutes the value −98.42 for −76.76.

 

I come up with 21% also

 Since both gave me the same # Im going to use that as my baseline :) I now have a goal to lose 11% Body fat, heh

Original Post by kmleela:

Hmmm....I take diuretics and I wonder if that screws with my Tanita readings...anyone have input?

According to this link at Wikipedia (not the best source, I know, but I think ok in this case), hydration is an important source of error when doing a BIA test (which is what the Tanita scales do to measure body fat).  Since diuretics affect the amount of water in the body, then I'm sure that it does indeed have an impact on getting accurate readings from your scale.

http://en.wikipedia.org/wiki/Body_fat_percent age#Bioelectrical_Impedance_Analysis

So although there are probably some problems with the formula the website uses to determine body fat, in your case, I would probably trust the estimate provided by the website over your scale as long as you are on diuretics. 

I wouldn't trust any of the online calculators. I just did several of them and came up with a greater than 25% difference among the different calculators. I have a scale that calculates body fat and water percentages which I use not to determine my actual percentages, but the variations in such.

elicarose:  This is not directed at you, so please don't be offended.

You know what amazes me.  I see on here all the time people who say that you shouldn't trust online calculators for body fat, BMR, etc. or that machines at the gym are no good at calculating calories expended, but at the same time blindly believe what this website tells them about how many calories are expended by a particular exercise or how many calories they should consume.

All of these things are just tools.  Some are better than others.  I think that pgeorgian has a good idea about using these types of calculators for body fat percentage.  Use them to get an idea of the trends.  If the calculated body fat percentage is going down and lean body mass is going up or is staying the same, then it is a good thing.  If it body fat percentage is going up or staying the same and lean body mass is going down, then it isn't.   The idea is just to get the numbers moving in the right direction.  The numbers themselves aren't as important.