Mathematical formula for detemining possible terminal length?

[FrannyG]

I was thinking about how some people have a lot of taper by the time they reach, say, waist length, while others don't. This seems to equate with overall terminal length.

Have any of you LHC geniuses come up with any sort of an equation or formula for determining terminal length based on nape circumference compared with a lower circumference? :graduate:

[harley mama]

Didn't there used to be a link in the old threads that you could use to calculate your terminal length? I don't think I ever tried it.

[FrannyG]

I think there was something about shed rate per day. I could never figure out how many hairs I lose in any given day.

I'm hoping more for something like an algebraic formula regarding taper.

[EdG]

Franny - here's a link to the terminal length formula http://forums.longhaircommunity.com/showthread.php?t=3245

It is based on shed rate. I think the answer is very approximate. :)
Ed

[FrannyG]

Thanks, Ed. :)

[danacc]

I was thinking about how some people have a lot of taper by the time they reach, say, waist length, while others don't. This seems to equate with overall terminal length.

Have any of you LHC geniuses come up with any sort of an equation or formula for determining terminal length based on nape circumference compared with a lower circumference? :graduate:

Unfortunately, there is no simple way to predict terminal length. Breakage also contributes to taper, and any trimming will change the nature of your taper once it grows past the trim point, too. If an equation relating terminal length to taper were developed, it would have to take into account amount of breakage and trim history as well. And how would you determine how much breakage exists?

In addition, based on what I've seen with my own hair, there seems to be different terminal lengths in different areas of my head. I assume this is highly individual (as are many things long-hair related, it seems).

[FrannyG]

I agree with you, danacc. There could never be an absolutely accurate predictor, but I still think that some sort of an algorithm could exist. Someone with a lot of breakage would have a false terminal length, but it would still be a terminal length for them. If we further took the fact that we all have many hairs that have a shorter natural terminal length and then factored in the amount of taper, I would think that we would be able to come up with some sort of a reasonable formula.

It wouldn't be completely accurate of course, but it might give an idea of what a realistic goal length might be.

[spidermom]

That would be a tough formula with many variables, I would think. For instance, before my March haircut I was at 34" with very thin ends. I imagine terminal length would have been predicted for me at that point to be not much longer than it was. Then I had it trimmed ??3-4 inches (didn't measure). Last length measurement six weeks later I was at 34.25" with much thicker ends. I recently had it trimmed back 1/2" again, so the ends are even thicker now. So if I calculated terminal length based on my ends now, I'm sure I'd be granted a longer possibility.

[harpgal]

Franny, from what I remember, Dianyla had figured something out about terminal length as related to taper. If no one comes along with an answer for you, I would PM her.

[FrannyG]

That would be a tough formula with many variables, I would think. For instance, before my March haircut I was at 34" with very thin ends. I imagine terminal length would have been predicted for me at that point to be not much longer than it was. Then I had it trimmed ??3-4 inches (didn't measure). Last length measurement six weeks later I was at 34.25" with much thicker ends. I recently had it trimmed back 1/2" again, so the ends are even thicker now. So if I calculated terminal length based on my ends now, I'm sure I'd be granted a longer possibility.


And perhaps you do have a longer possibility now with that damage gone. As I said in my last post, even artificial terminal caused by damage and breakage could be determined perhaps. Maybe if you hadn't had that trim your hair would not have the same chance for gaining as much length as it does now.

For example, my daughter went almost 3 years without getting her hair cut. In the summer of 2006, her hair was hovering just above waistlength. In the summer of 2007, her hair was still hovering above waistlength. Although we know she had growth in that year, it didn't show in her length, so she had an artificial terminal length.

I agree that there are a lot of variables. I just think that there's probably someone on the planet who's as much of a geek as me, but who has the brains to actually figure this out. :)

[FrannyG]

Franny, from what I remember, Dianyla had figured something out about terminal length as related to taper. If no one comes along with an answer for you, I would PM her.

Thank you harpgal! :)

[Bill D.]

In addition, based on what I've seen with my own hair, there seems to be different terminal lengths in different areas of my head. I assume this is highly individual (as are many things long-hair related, it seems).

This seems to be typical from what I've seen, though the pattern and degree may vary some. When the hair was thick all over my scalp (before male pattern baldness), the longest hairs were coming out of the back of my head about an inch below the top of my head. These hairs actually reached lower down my back than the hairs coming out lower down on the back of my head.

Another factor is that hairs seem to slow down as they get closer to terminal length. People trying to reach terminal length commonly report that the final inches take the longest.

Bill D.

[Dianyla]

Franny, from what I remember, Dianyla had figured something out about terminal length as related to taper. If no one comes along with an answer for you, I would PM her.
Thanks for the shout-out, harpgal! :)

What I did was take length and circumference measurements of my (then just-past-knee-length) hair. I started at my nape and took measurements every six inches down to the ends. Then I did a linear regression on the data points. Terminal length is the future predicted point where the circumference drops to zero.

However, I did a few things wrong as we discussed in this other thread (http://forums.longhaircommunity.com/showthread.php?t=3245). I should have used the circumference to calculate area, and then determined it based on that. I think that the area will decrease linearly, but not the circumference.

Now that I've got about a foot more hair, and I'm getting even closer to terminal length, I need to get around to redoing this measurement task. :)

[Cinnamon Hair]

I think we would need to see someone grow to terminal, while measuring every so often, to validate the theory.

On some people (myself included) the point where hair begins to noticably thin moves downward over time as slower growing hairs catch up.