Bowie Knife Lengths

Oct 15, 2001
Can anyone tell me what were the ranges of blade lengths of Bowie Knives used during the Civil War and Cowboy eras? I see Bowie knives represented as being like those from that era with a wide range of sizes (e.g. 6" to 15") and wonder if they were really that divergent at that time.

Ken Cox

Dec 11, 1998
A Bowie knife measures 13.5" from butt to tip, with 8.343" of blade and 5.157" of handle.

I thought everyone knew this. :)

Thirteen and a half inches represents the length of the average man's inner forearm measured from the inside of the bent elbow to the inside of the bent middle finger.
This correlates to the standard "pull" of an American military rifle, or the distance from the trigger to the butt plate.

If a man's personal dimensions vary from this, the length of his Bowie should vary accordingly.
This man should then multiply the length of his proposed Bowie by .618, and this will give him the correct blade length for his body.

For example:

Bend the elbow 90 degrees and also curl the fingers so that the middle finger points to the elbow.
With an 18" ruler, measure the distance from the inside of the bent elbow to the inside of the curled middle finger.
This gives the total length of the whole knife.
Multiply this distance by .618 for the blade length and subtract that product from the total length in order to determine the handle length.
A Bowie made to these proportions will fit the man.

For me, this means a 13.5" knife with an 8.34" blade and a 5.157" handle.

Now it gets interesting:

Multiply the length of the blade again by .618, and subtract that product from the total length of the blade.

In this case, multiply 8.34" by .618, which gives 5.15412"; and then subtract 5.15412" from 8.34", which gives 3.18588" or the length of the clip.

So, now we have a 13.5" knife with an 8.34" blade that has a 3.18588" clip.

It gets even more interesting:

In order to determine the location of the point, take the width of the blade and multiply it by .618.
With a Bowie made from 2" stock, one would multiply 2" by .618, which gives 1.236".
The point on this blade would then fall 1.236" from the top of the blade, and rise .764" from the bottom of the blade.

Try drawing this knife.
It looks a lot like a Randall #1.

I imagine Gene Osborn of would make this knife to the buyer's tastes for a reasonable price.
Jan 14, 2002
Hey Ken,

This is fascinating. Everybody most definitely does not know this. I would love to know where this formula comes from. Is it found in any historical documents or is it a modern thing?
Very curious.

Ken Cox

Dec 11, 1998
The .618 comes from Fibonacci's series, or the Golden Section.

Architects have used the ratio of 1.618 to 1 (same as .618) for thousands of years.
For some reason human beings find it aesthetically pleasing.

Anyway, Fibonacci's series goes like this:

1+2=3, 2+3=5, 3+5=8, 5+8=13, 8+13=21, and on and on.

See the pattern?

If one divides the next lower number into the next higher number, one gets closer and closer to 1.618 as one gets higher in the series.
This number, 1.618 has many other amazing properties and I recommend doing an internet search for the Golden Section or Phi.

Try this:

In any event, some years back I undertook the design of an historically accurate biblical sword, trying to work from the evidence available.
Eventually I had the sword made and it appeared as part of an article written by me in the October 2000 Knives Illustrated as the Sword of Ehud.

I had very strong evidence that this sword measured 13.5", or one gomed, a measure derived from the 18" biblical measure called a cubit.
(13.5" sounds short for a sword, I know; bear with me)
At the same time I read on the Randall Made Knives site that they considered a knife, specifically the #1 and #2, made to the proportions described earlier (actually, 13 X 8 X 5) as the best handling combat or fighting knife.
I immediately recognized the 13 X 8 X 5 numbers as part of the Fibonacci series.

Therefore, I incorporated the number 1.618 or .618 in my design wherever I could.
In this case, I designed what looks like a dagger.
However, early on in the fabrication of the knife/sword, Gene Osborn, the maker, remarked that the knife felt unusually powerful for a dagger.
Now that I have the finished knife, I can attest to its unusual balance and "power."

Now, the short sword in question belonged to a Benjamite judge and warrior named Ehud, who used it to assassinate a king.
We know that he strapped it to his thigh and smuggled it past the king's body guards.
We also know that Ehud described it as one cubit in length.
Well in those days they used the word cubit to mean both the gomed, 13.5", and the cubit, 18".
So, I decided to make the same exact sword myself, this time 18" but scaled exactly to the 13.5" version.
This results in an 11.124" blade and a 6.876" handle.
Amazingly, this knife also handles like lightning and will chop down a telephone pole (mild exaggeration).

Here comes the interesting thing about 18", or a cubit.
Remember, the gomed equals the inside of the forearm.
The cubit then equals the distance from the outside of the elbow to the outside of the curved middle finger.
This distance has great import to archers, although I cannot say why; but it does.
This distance also happens to equal the distance from the center of rotation of the hip to the center of rotation of the knee.
In a small person or a large person, that distance may vary but the distance from knee to hip will always equal the distance from outside elbow to outside middle knuckle.
Gomed eguals inside and cubit equals outside.

One can strap a gomed length knife to the inside of one's thigh, and still safely kneel without "painting" the knife; similarly, one can strap a cubit length knife to the outside of one's thigh and still kneel.
Most relevant to this conversation, though, if the maker can cause the knife to balance at the Golden Section, it handles in a manner which one cannot appreciate or imagine until he feels it for himself.
Therefore, I surmised that the Bowie knife, in order to manifest the qualities ascribed to it, must also balance at the Golden section.

So far, I only have two knives which balance exactly at the Golden Section, and they both handle like a dream.
They both also derive their overall lenght from body proportions; I don't how much of a factor this presents, though.
I can only report what I've experienced.

I have to go to bed.
I haven't edited this; I hope it makes sense.
Apr 6, 2001
:D Wow! This is really cool!
Thanks for the information... dunno what else to say, dont have anything to add, but yeah, thanks for posting all that. :)
Feb 12, 2001
Very interesting info, Ken. Thanks for posting it. Do you have any pictures of your sword? I would love to see it. Now when people ask me how big my white river bowie is, I can tell them that it is one cubit in length, but that the handle to blade ratio does not conform to Fibonacci's series:D .