How accurate are body fat % scales?

Because I bought one today and it says my body fat % is 14.4% but I have a hard time believing this. I always thought it would be more like 20%.. I'm 5'9 and 114lbs.. but I'm completely untoned and have lots of visible fat so...

Accuracy varies with how hydrated you are. Other issues. But they can be reasonable.

I'm 5'9" 163lbs and about 13%. You're fairly light for 5'9". Kind of hard to have lots of excess fat at that weight.

zeke, being as sunkissed is a women, her % body fat will naturally run higher than a man's.  If I remember correctly 20% would be average and 14.4 would be pretty good.

I have always wonder how those scales work, love to know mine, I'm 5'9" as well but 140 pounds, and one website I was at put me at 7%

Mine says 24% and my grandma's says 17%... So it kind of confuses me also seeing I have very little fat at all or muscle... Except in my bum and chest... then again my feet are usually dirty so it prolly messes with the electric charge that goes through your feet.

Btw, dun wear socks on scales that tell of fat and/or water percent.

The scale sends an electrical pulse up one foot and back to the other. I guess it then registers the ristance and checks it against a formula.


I understand she is female but she's is way too light for 5'9".  IIRC 14.4% is too low for most women.

even as a woman 20% is not really average (http://www.healthchecksystems.com/bodyfat.htm ) ... 14.4% is low unless you are a serious athlete.

you are 5'9" ... 114 is too light already, you certainly do not need to be 106lbs. i think it's highly doubtful you have 'lots of visible fat' ... maybe you should rethink your goals? stay healthy. :)

sorry guys, guess i'll have to bone up a bit more on body fat!  I completely missed her weight and height in her post.

Yes they are right you are way too light, sunnkissed.

Thanks Zeke, I have seen these scales at lots of places ane man they run the gambit of prices!!

I don't think the scales get better with price. They may read smaller fractions but I bet it's basically the same scale.

Likely better to buy a basic scale and use the rest of the money to buy a set of calipers. Use the scale to track. Then use the calipers every so often.

But this depends on you learning to use the calipers well.

I have read that the scales read HIGH for women. So your true body fat % may actually be even lower than 14.4%.

If you are not an athlete, then this is concerning. Do you have periods?

I bought a scale with a BF reading about 6 years ago.  I accepted the readings as not unreasonable until last year when my weight and waistline dropped dramatically as a result of a very serious training program.  My scale kept reporting my %BF up in the upper twenties.

The problem with my scale is that it considers age as a key factor in determing your %BF.  In one morning, I changed my reported age several times and each time the %BF changed accordingly.

Based on the results of an on-line body fat calculation that uses hips, waistline, wrist and forearm,  I am currently at about 19%.  This agrees with a skin-fold measurement made at the gym and some other calculations that I have done.  So I calibrated my scale by adjusting my reported age down until I got the same number.

I just plugged your height and weight into a calculator and it says that your ideal weight should be 131 to 160 pounds. I also realized after checking your profile that you are only 15 years old. You should not be dieting at all. If you are worried about being untoned, exercise.

Mine has you put in your age sex height and wether you are athletic or not the definition it uses for athlete is work out daily I am but must say I like the calc it gives me as a non athlete better LOL

My daughter got on it once and her BF% registered at 11% she is very thin 5'6" and 105 lbs she is trying to gain weight, 

If you are 5'9" adn 114lbs you are probably underweight and that 14.4% is probably about right.  at my height of 5'6" I think the least I should weigh is 115

I dont really think u should even be worried about your weight .114 pounds and 5'9, i seen girls that weight a 114 pounds and there 5 foot tall and they look pretty thin

I was wondering the same question. i have a scale that shows approximate body fat % and it says mine is 41%

With what I said earlier, my scale only takes in age, sex, and height... Whereas my grandmas takes in age, sex, height, frame size, and if you're an athlete or not.

The scale BIA testers are generally not accurate or reliable at all. Hydrostatic testing is probable the most accurate way to measure (although not very practical for most people :) ), skinfold testing is close second and the only practical, reliable method.

There was a study late last year IIRC. Skin fold is only reliable if the person doing it is. Seems the study found the scales better then the average person with calipers.

That's the key. Learn to do it properly, and you're better off than with the scale. Or see a doctor who knows how to do it.

It seems to me that there are two different discussions running here.  One is about a young lady who weighs in at 114 pounds although she is 5' 9".  Her %BF is probably so low that trying to measure it would be ridiculous.  As others have said, she should be targeting her diet to promote healthy growth.

As far as I know, there is no absolutely perfect way to measure per cent body fat.  Even hydrostatic testing involves assumptions about body composition.  When Archimedes invented the process, he only had to determine whether an intricately designed crown was or was not gold.  In comparison, a human body has fluids, bone, muscle, fat and possibly other stuff.  Bone density, for example, varies from one body to another.  So the result of a hydrostatic test is a good estimate of %BF.  Skin fold test also produces a good estimate of %BF.  Electronic measurements are not dependent on the skill of a human tester and there for more repeatable.  But if the software that produces the %BF uses an invalid assumption, then the result it produces is meaningless.  The technical term for that is "Garbage In, Garbage Out."

In the case of the scale that I use, the calculations depend on assumptions about the effect of aging that are not necessarily valid.  If I tell the scale that I am 63 years old, it produces one result.  If I then tell the scale that I am 40 years old, it produces a different, lower %BF for the same weight and resistivity values.  If I then tell the scale that I am 30 years old, it produces an even lower result.  If I then tell it that I am 63 years old, it reproduces the original result.  The only thing that changed in the 15 or 20 minutes required to perform that experiment was my reported age.

The guy at the gym who did the skin fold measurements for me told me that my lean body mass was 144 pounds.  I have no idea whether he was actually good at skin fold tests or not.  But if I go to the website, http://www.healthcentral.com/cooltools/nutrit ion/homebodyfattest.aspx, and get a reading on my %BF, it also informs me that my lean body mass is about 144 pounds.  So I have two independent estimates that agree very closely.  If I tell my bathroom scale that I am 31 years old, it produces a %BF reading that corresponds to a lean body mass of about 142 pounds.  So that is what I tell my bathroom scale.

While %BF is a key health indicator and much more generally applicable than the BMI, all of this is not terribly important.  I had to go out and buy new slacks and a new belt when my weight went through the floor last summer.  As long as those pants and belts fit comfortably, my %BF is okay.  I only check my weight and %BF every morning because, they will tell me long before my pants do that I am overeating and that I need to make appropriate changes.

I recently had mine done.  He told me that 22% was AVERAGE for women.  He also said that 17% is the LOWEST that women should be.  Considering your height, I would have guessed you as underweight, and I think the BF% is proof of that.  Kelly

with the tanita scales, the nighttime readings are more accurate for body fat, because the body is more hydrated.  The hydration level affects the scale's ability to differentiate between fat and lean mass.

so all of you that use the BF scales, weigh in the morning for accurate weight, but weigh at night for accurate BF.