Accuracy of methods of calculating Body Fat %

13hirteen

I'm looking to track my body fat more than my weight or BMI, as I'm actively trying to build muscle at the moment. I've been doing pretty well and have lost around 5% body fat in the last month, based on measurements. However, I recently found an alternative body fat measurement calculator which throws up radically different results to the one I've been using so far.

The calculator I started with and still use as my main reference, at http://lowcarbdiets.about.com/library/blbodyfatcalculator.htm is based solely on height, neck, waist and hip measurements. That currently puts me at 35.5% body fat.

However this calculator - http://www.bmi-calculator.net/body-fat-calculator/ - uses wrist and forearm measurements as well. It puts my body fat at 27.5%

It's not much of a concern while I'm still over-fat, as all I want is to see the numbers going down, but I'd like to make sure that I'm not vastly over- or under-estimating my fat levels in the long term.

If it's of any relevance (not that it should be when it comes to Body Fat %), I'm 170cm tall and currently weigh 78kg, so have a BMI of 27. I've got a fair bit of muscle, although I let myself go to seed after an injury last year, but I've not measured my body fat before I started this month, so have no baseline to work from.

jamielynn1981

You could try body fat calipers. They are pretty cheap and relatively accurate. I usually use these and my scale which gives about the same %.

Fattack

Bump. Interested to what people say about this. I would have thought that the latter calculation, as it accounts for your arm and forearm maybe somehow is trying to calculate your frame size too? I have no idea! My omron scales put me at 40% body fat, but the US navy one puts me at 29%. (My BMI is 26.8).

rileamoyer

Contact your local health clinic and find out about a body composition scan. Here in US they are fairly cheap. Or find a measurement that includes elbow joint measurement vs. wrist. I found it to be closer in determining your bone structure..

thetrishwarp

I tried the first one and got 26.3 and the second one gave me 26.1, so I personally didn't get much of a difference between the two. In terms of an alternative method, try body calipers or find a place with a bodpod.

DebiP10

big difference in these 2 sites. the first site said mine was 18% and the second site said 24% so i wouldnt say they were accurate. body fat callipers are ment to be the best way but there hard to work out unless your pretty good with math

lausa22

I got a HUGEEEE difference. From 44% on the first site, to 26% on the other.
Obviously one of them aren't accurate.
I'd contact a clinic to get a accurate result, myself.

rileysowner

From best to worst in my opinion and what I have read:

Dexa (I may have the name wrong) which is a test using x-rays to determine body composition. Expensive and not accessible for most of us.

Under water weighing/Bod Pod -- different methods but both are considered very accurate. Again, not to accessible for most of us.

Calipers -- Can be quite accurate in the hands of an experienced person, but prone to operator error. You can measure certain point yourself, or have someone else do it for you. They are inexpensive and fairly accurate if you take multiple readings and average them out. There are lots of web-sites that will do the math for you to get BF%.

Electrical Impedance -- This is what the scales and the hand held body fat measuring devices use. It has a fairly large margin of error, but can be ok for a general idea.

Body Measurements -- These are quite inaccurate due to the fact you need to measure at exactly the right place among other things. I personally don't think these are worth the time it takes to measure yourself.

I would suggest either finding some place that will do caliper or bod pod measurements for you at a small cost or pick up some calipers of your own (Accu-measure is one name brand) and do your own measurements.

vinnysgirl

I looked into this yesterday and got a real big shock :noway:

My BMI is 22
My height is 5'6"
my weight is 134.75lb

The calculator (which measured height, weight, gender, age, hip, waist, wrist and arms)
said I had 32% body fat and that I was OBESE !!

13hirteen

Thanks, folks.
I've ordered a pair of budget callipers and am looking into local body fat measuring services.

shander7

I would trust the 2nd one more I think.. I got 15% on the first one and I am definitely NOT 15%! The second said 24% and I think that is closer to what I probably am