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View Full Version : Measuring Hair Thickness...and why your number might be wrong



divinedobbie
April 26th, 2014, 11:46 AM
I have been cursed with a little 2.5" ponytail circumference. I keep hoping that my tape measure is lying to me or that my hair will get thicker as I take better care of it so I measure it obsessively every month. Well it's been 8 months since I had extensions (I lost a lot of hair!) and about a year since I've started growing out my bangs. I figure that all my new growth should be about 4" long and my bangs about 6". Maybe all those short hairs just aren't getting into that one ponytail on top of my head and it's giving me a smaller number than it should be.

Someone recommended a really great idea in another thread. Divide your hair into two ponytails so that it gets all your shorter hairs, measure each ponytail separately, add the two numbers, and voila you have your real thickness!

After doing that, I got a 2" circumference for one ponytail and just over 1.5" on the second...which means I have a 3.5" circumference! Oh, I was so excited and in hair heaven!!

WRONG. :(

After my initial euphoria wore off, I started thinking about how that's even impossible. I can't put my finger on it exactly but I remember something about being able to increase surface area but still have the same volume. I repeated the tests by continuing to divide my hair into more sections, and sure enough, the overall circumference kept increasing.

Sadly enough, that means I still have a 2.5" ponytail. And unfortunately according to my theory, some of you who might have been measuring your hair and bangs separately, actually have a false number.

So am I right? And is there a way or formula to be able to measure my hair in two ponytails but still get an accurate overall circumference?

Tall Blond(ish)
April 26th, 2014, 12:11 PM
I won't bore you with the math details, but your conclusion is correct.

ExpectoPatronum
April 26th, 2014, 12:23 PM
This is why I don't measure my bangs separately. What I do is measure one ponytail without my bangs and then make another ponytail higher up to include my bangs. I take both those measurements and take the average. It may not be super accurate, but it at least accounts for my bangs.

Seeshami
April 26th, 2014, 12:24 PM
I never thought to include my bangs in my pony tail... :confused:

darklyndsea
April 26th, 2014, 12:38 PM
If you want to get your true circumference from two or more ponytails, you have to do math.

Measure your ponytails' circumferences. Write each down separately (don't add them together). circumference=2*pi*r; solve for r: r= C/(2*pi). area=pi*r*r. Add the areas together. find the radius of that area: sqrt(area/pi). Use that radius to find the circumference: C=2*pi*r.

jeanniet
April 26th, 2014, 01:26 PM
Don't get hung up on measuring thickness. If it gets significantly thicker, you'll know. If you must measure, just use a circle with your thumb and forefinger. It's reasonably accurate but doesn't give you a number to obsess over--and again, if your thickness increases, you'll know.

LongHairLesbian
April 26th, 2014, 02:29 PM
What's wrong with having a 2.5 inch pony? Bigger doesn't mean better, your hair is lovely and grows nicely as it is, it doesn't need to be any thicker to be beautiful. :) I'll admit to being a bit obsessive about my hair's thickness; I'm guessing it's somewhere in the ii range, but I won't actually measure it, because I don't want to let a number define how confident I am or am not about my hair. You have beautiful hair, you don't need to change a thing. :)

lapushka
April 26th, 2014, 03:08 PM
What's wrong with having a 2.5 inch pony? Bigger doesn't mean better, your hair is lovely and grows nicely as it is, it doesn't need to be any thicker to be beautiful. :) I'll admit to being a bit obsessive about my hair's thickness; I'm guessing it's somewhere in the ii range, but I won't actually measure it, because I don't want to let a number define how confident I am or am not about my hair. You have beautiful hair, you don't need to change a thing. :)

Totally agreeing with this. What's this "obsession" with thick hair, anyway. It's not all that great over on this side (iii), you know. ;)

jeanniet
April 26th, 2014, 03:27 PM
What's wrong with having a 2.5 inch pony? Bigger doesn't mean better, your hair is lovely and grows nicely as it is, it doesn't need to be any thicker to be beautiful. :) I'll admit to being a bit obsessive about my hair's thickness; I'm guessing it's somewhere in the ii range, but I won't actually measure it, because I don't want to let a number define how confident I am or am not about my hair. You have beautiful hair, you don't need to change a thing. :)

Not a thing. I think i hair is beautiful, as is ii. iii hair is quite often a PITA, and IMO doesn't look any better (especially on a windy day). I guess it's easy for me to say, since I have iii hair, but if the people with i/ii knew how much I fought and despaired over this much hair for most of my life...! It's better now because I've learned to work with it instead of trying to control it, but it will never, ever be tamed.

kaydana
April 26th, 2014, 03:28 PM
If you want to get your true circumference from two or more ponytails, you have to do math.

Measure your ponytails' circumferences. Write each down separately (don't add them together). circumference=2*pi*r; solve for r: r= C/(2*pi). area=pi*r*r. Add the areas together. find the radius of that area: sqrt(area/pi). Use that radius to find the circumference: C=2*pi*r.

This is correct, but there's no need to do quite that much work. It simplifies down to

c = sqrt(a^2 + b^2)

Where a and b are the two measured circumferences, and c is the total circumference of all the hair.

So, in this case:

c = sqrt(2^2 + 1.5^2)
c = 2.5

Still 2.5" I'm afraid, which is to be expected really, because half inches aren't nearly precise enough for the kinds of increases you'll get measuring in two ponytails rather than one.

MsBubbles
April 26th, 2014, 03:29 PM
It's not all that great over on this side (iii), you know. ;)

Oh! Easy for you to say...:laugh:

I have another theory that hairline width has a lot to do with how 'thick' a hemline could appear down a person's back. I have a tiny head. It's hard for me to spread my fine hair out for photos. I also have a pretty wide back, so this can make my hair seem 'thin', even though I'm consistently at a 3.25" ponytail (during the non-shed years).

Not calling people with fanned-hemlines big-headed either, though. :silly: It's just there are so many variations on how it all looks. It's all pretty.

lapushka
April 26th, 2014, 03:35 PM
Oh! Easy for you to say...:laugh:

Hey, I struggled with this mess I call hair for all of my life! :) I know what living with iii hair is, and I do not get for one minute why i and iis are striving to increase thickness - at all. Be content with what you've got, that's my motto (now that's easy for me to say) :laugh:

eadwine
April 26th, 2014, 03:36 PM
This is correct, but there's no need to do quite that much work. It simplifies down to

c = sqrt(a^2 + b^2)

Where a and b are the two measured circumferences, and c is the total circumference of all the hair.

So, in this case:

c = sqrt(2^2 + 1.5^2)
c = 2.5

Still 2.5" I'm afraid, which is to be expected really, because half inches aren't nearly precise enough for the kinds of increases you'll get measuring in two ponytails rather than one.

*crosses eyes*

I think I will change my ii to: I have hair.

;)

MsBubbles
April 26th, 2014, 03:50 PM
Lapushka...I think I just will be forever traumatized for having the misfortune of having to go through the Big-Hair 1980s as an insecure, impressionable teen with 1a/f/ii hair! :D

I try occasionally to imagine how hard it must be to battle a huge curtain of thick, ample hair. Can't do it. But I can in theory understand it must be cumbersome at times.

ETA: Eadwine...that's good! :lol:

darklyndsea
April 26th, 2014, 03:54 PM
This is correct, but there's no need to do quite that much work. It simplifies down to

c = sqrt(a^2 + b^2)

Where a and b are the two measured circumferences, and c is the total circumference of all the hair.

So, in this case:

c = sqrt(2^2 + 1.5^2)
c = 2.5

Still 2.5" I'm afraid, which is to be expected really, because half inches aren't nearly precise enough for the kinds of increases you'll get measuring in two ponytails rather than one.

This is kind of odd, but when I do this sort of thing I do each step in order because I'm too lazy to simplify the equations. :P

lapushka
April 26th, 2014, 04:07 PM
Lapushka...I think I just will be forever traumatized for having the misfortune of having to go through the Big-Hair 1980s as an insecure, impressionable teen with 1a/f/ii hair! :D

I try occasionally to imagine how hard it must be to battle a huge curtain of thick, ample hair. Can't do it. But I can in theory understand it must be cumbersome at times.

Oh I remember the eighties. :lol: Wore my hair mostly crimped (that was about as big as a perm would be in those days) with a bit of a pouf in front. Oh the memories. :oops:

Larki
April 26th, 2014, 04:18 PM
I've never bothered to figure out what my circumference is with my bangs included. I have fairly thick bangs, but it doesn't seem like they make that much of a difference.

kaydana
April 26th, 2014, 05:54 PM
This is kind of odd, but when I do this sort of thing I do each step in order because I'm too lazy to simplify the equations. :P

Are you implying I'm not lazy? I'm almost offended. :p

I didn't actually simplify it, I knew the answer already. Quoting you and saying "it simplifies down to..." just seemed like the easiest way to explain why I've given a well known equation most commonly associated with triangles as the answer to a question about circles.

MsBubbles
April 26th, 2014, 06:24 PM
Oh I remember the eighties. :lol: Wore my hair mostly crimped (that was about as big as a perm would be in those days) with a bit of a pouf in front. Oh the memories. :oops:

Oh I was so envious of my friends who could crimp their hair! (any attempt at curls, kinks or waves just never stuck for me).

I wonder if that'll ever really be a thing, again. :hmm:

darklyndsea
April 26th, 2014, 07:54 PM
Are you implying I'm not lazy? I'm almost offended. :p

I didn't actually simplify it, I knew the answer already. Quoting you and saying "it simplifies down to..." just seemed like the easiest way to explain why I've given a well known equation most commonly associated with triangles as the answer to a question about circles.

Well, you did go to the effort of memorizing at least one more equation than I did... ;)

chen bao jun
April 26th, 2014, 08:12 PM
Bottom line, your hair is VERY pretty, 2.5 is not a small circumference, it is average and you can do all the complicated math to find out your 'real' circumference if you wnat to, but I don't think the ponytail measurement is all that accurate in any case. I certainly keep getting different numbers each time I bother to measure (which isn't all that often).
It's sad enough that we here on LHC sometimes start obsessing about our hair growth, which is silly because hair takes a long time to grow to the lengths many of us desire. It will be even sadder if we obsess about hair thickness, which may change slightly from being on here, because poor hair care may mean that we've been yanking out hairs before their time, but isn't going to change much. People just don't grow new hair follicles, no matter what product they use, what they eat and how well they take care of their hair. It's genetic and that is really that.
I never thought to include my bangs in my ponytail either, by the way.

Emichiee
April 26th, 2014, 08:27 PM
Even wrapping a tape around your hair is not the most accurate way to tell how much hair you have. Coarser hair will get a thicker circumference even with less hair and the other way around. I think we should see the ponytail measurement as a not so accurate way that only helps us to do a rough comparison when we try to find hair twins for inspiration. Or to document changes in thickness...when I lose hair I can really see the measurement change, as well when it thickens up again.

majesticgoldenr
April 26th, 2014, 08:50 PM
Today I sat down and did mine with a ponytail and scraps of paper I marked and measured after. Dont like the results, but knowing that they're pretty much not accurate makes me feel a little better :)

divinedobbie
April 27th, 2014, 12:54 AM
Thank you for all the answers :).

The reason it makes me a little upset my hairs not thicker is because I feel incredibly limited in my style options. I dont have enough hair for a lot of really awesome updos like crown braids, waterfall braids etc. I guess "obsessed" was too strong of a word to use, im just curious if my new hair habits have any noticeable results.Im really afraid that the extensions might have pernamently damaged my hair follicles so Im clinging to all hope that my hair will still grow back.

As for not measuring and just being able to notice a change in thickness - I dont trust my mind ;) i like to have solid evidence.

Thank you for the math formula, that's exactly what I was looking for. I really hate math myself, taking calculus was the worst decision of my college career.

Hedera
April 27th, 2014, 02:53 AM
Thank you for all the answers :).

The reason it makes me a little upset my hairs not thicker is because I feel incredibly limited in my style options. I dont have enough hair for a lot of really awesome updos like crown braids, waterfall braids etc. I guess "obsessed" was too strong of a word to use, im just curious if my new hair habits have any noticeable results.Im really afraid that the extensions might have pernamently damaged my hair follicles so Im clinging to all hope that my hair will still grow back.

As for not measuring and just being able to notice a change in thickness - I dont trust my mind ;) i like to have solid evidence.

Thank you for the math formula, that's exactly what I was looking for. I really hate math myself, taking calculus was the worst decision of my college career.

Yeah, I like being able to measure as well; sometimes I am absolutely convinced that my hair has thinned horribly, but when I measure it it turns out to be the same as always.

My thickness tends to be a very consistent 2.5 to 2.75 inches.

I wonder about the crown braids though; when my hair was longer I was able to do those and it didn't seem that thickness (or lack of it) was in any way a problem.
Having hair much longer than BSL made it more difficult (this is one of those styles for me that is easier when around APL or slightly longer) and of course the direction change was the greatest difficulty, but it's one of the few styles I've found where thickness of hair does not make that much difference in my ability to do it, or even the way it looks.

lapushka
April 27th, 2014, 08:20 AM
The reason it makes me a little upset my hairs not thicker is because I feel incredibly limited in my style options. I dont have enough hair for a lot of really awesome updos like crown braids, waterfall braids etc. I guess "obsessed" was too strong of a word to use, im just curious if my new hair habits have any noticeable results.Im really afraid that the extensions might have pernamently damaged my hair follicles so Im clinging to all hope that my hair will still grow back.

OTOH you are able to do updos and buns at a much shorter length than someone with iii hair! I needed to wait until I reached waist/hip for the simplest of buns.