The Ancient Origins of the Cubit

Author’s Note: Since my teenage years I’ve loved to investigate subjects which are related in some way to ancient history and the Bible.   During the late 19th century and the early 20th century there was much interest and many books written about the Great Pyramid.  Many of these books claimed the Great Pyramid was an ancient chronograph and contained hidden scientific knowledge.  Some even claimed a connection to Biblical history.   I don’t intent to discuss the veracity of those claims in this current article but I would like to address a related subject.

 The subject of this current article is the origins of the ancient cubit and its relationship to linear measure and geometry.  Many of the ideas in this present essay have their origins in those books from the turn of the 19th century.  I have tried to condense and simplify some of the ideas and principles.  I can only take credit for trying to refresh some of their great research.  After over 20 years of investigation I am humbled by how ignorant we are of the past.  I am equally astounded by how much those ancient “primitive” civilizations knew.  As this article will demonstrate those civilizations used advanced mathematical concepts in normal everyday life, concepts that modern science did not “discover” until thousands of years later. So without further introduction I hope you enjoy:


The Ancient Origins of the Cubit: Its Basis in Linear Measure and Geometry

The cubit is a unit of measure which was used across the ancient world.  It was defined by a unit of measure related to our modern inch.  While the exact date and origin of the inch based system has not been determined in history, it is represented in almost every culture with only a very slight variation over thousands of years. Interestingly, the original primitive “inch” seems to have represented a fraction of the polar diameter of the earth. It is approximately a 1/500,000,000th fraction of this polar diameter. Pretty amazing considering its antiquity.
Up until the French revolution the inch based system was without rival. It is the basis for the foot, yard, furlong, cubit, mile, and numerous other specific measurements. The table below was compiled by Piazzi Smyth. It is found in his book The Great Pyramid.  He was the astronomer-royal for Scotland in the late nineteenth century. His list shows the value of the inch in various cultures as a fraction of the foot. Our modern inch today is closely related to the British inch. One of the oldest surviving representation of the inch is found in the Pyramid of Gizeh. The entire system of geometry represented in this ancient structure is based on an inch. This ancient or for lack of a better term “primitive” (P) inch is equal to P = 1.0011” British inches. Ancient Greece is credited with the discovery of modern mathematics and geometry. But upon close examination each “great” Greek scholar was “inspired” only after a period of time spent in Ancient Egypt.   The fact of the matter is that ancient Egypt showed a knowledge of Pi and other complex mathematical relationships  long before the Greeks showed up and borrowed the ideas.   Some of Egypt’s most basic linear and square measures are derived from Pi.

Today one of the most misunderstood and confused measurements of ancient origin is the cubit. Some claim the cubit is approximately 18”, while others claim 20”.   Most evidence today points to a variation of one of these two measurements.    In ancient Egypt there is also evidence of another cubit of 25”.   According to Petrie and others this cubit saw use when Egypt was under Semitic influence.

The two most widely recognized forms of the cubit are merely an expression of the relationship between the year of 365.25 days and pi. (3.14159). In ancient Egypt the Aroura was an area measurement equal to the expression of this relationship.   In Egypt the year was sometimes called a quarter (1/4). This “quarter” was the geometrical expression of a circle whose circumference was 3652.5”.   This circle or “quarter” had a diameter of 1162.6” and was equal to a “quarter” of an Aroura.  4 of these “quarters” were equal to 1 Aroura. In order to further simplify this relationship a rectangle Aroura of 1162.6 P” x 3652.5 P” was developed.   This rectangle was the equivalent area measure of 4 of the 1/4 Aroura circles.   This rectangular Aroura was then expressed as a square Aroura of 2060.7” x 2060.7”.    A linear cubit was then derived from 1/100th of the side of this square Aroura.  A square cubit was equal to 1/10,000th of this square Aroura.  The following table expresses these relationships.

The second cubit used in ancient Egypt was also a variation on the relationship between the 365.25 day year and Pi.  This cubit was the Egyptian Pi “rod” cubit or circumferential cubit.  This cubit or rod measurement was a fractional measure of  half  the circumference of this 1/4 Aroura “year” circle of  3652.5”.   This linear cubit measure was equal to 18.2625” and was a linear expression of the relationship between the radius of a “year” circle and its circumference.   The next two tables show the means by which the Pi / year relationship was expressed and  the means by which both cubits were derived.    They also show the relationship between these Egyptian cubits and their inch and diametric divisions.

Horapollo in his Hieroglyphics, Bk I, v. stated the following concerning the relationship between the Egyptian year and the Aroura: To represent the current year, they (the Egyptians) depicted the fourth part of an aroura:  now the aroura is a measure of land of  an hundred cubits.  And when they would express a year they say a quarter.”

Hereodotus makes a similar statement:  “the aroura is a square of a hundred cubits, the Egyptian cubit being the same as the Samian.” 

As you can see the cubit of 20.607” and 18.26” both had origins in practical geometry and linear measure. Most cubit approximations today are based on one of these two cubits. A cubit then is a linear measure expressing the relationship between the 365.25 day year and Pi.   This relationship is the reason the ancient Egyptians sometimes expressed the year in hieroglyphics as either a square or a circle.

The evidence for a sacred cubit of Semitic origins is compelling as well.    It is claimed by Davidson and others that Mr. Flinders Petrie, the eminent Egyptologist, found that the 25” cubit was used in Egypt during the XVIII Dynasty. (I have not been able to verify this claim as a reader graciously pointed out to me recently.) This was a period of time when the Egyptian culture was heavily influenced by Semitic culture. According to him the  25” cubit is only found during periods of Semitic influence.    Mr. Petrie also found the half-cubit or “foot” appeared in Babylonia as a foot of 12.5”. In Greece this “foot” was 12.44-12.62 B” (British inches) in Eturia it averaged 12.47 B”.

In the 10th century the “foot” was shortened to 12”. This became the legal foot since that time. For an extended period of time the 12” legal foot competed with the old half-cubit foot (12.5”) of antiquity.  Evidence for this is found in several places but one of the most compelling modern examples is found on the statue of Richard I from  1199 AD.   An inscription on this statue defines an acre as follows: “40 perches in length and 4 in breadth and every perch of 16 feet in length”  

According to this inscription the perch was only 16 feet in length.  A modern perch on the other hand is 16.5 feet in length.   The discrepancy is obvious when it is realized that a foot at the time of this inscription was 12.5” in length while the modern foot was shortened to only 12”.    Therefore the perch at the time of Richard I was 200” in length while the modern perch is 198”.   The modern perch being lengthened so that it could maintain its value (within 1%) relative to the inch as defined by the shortened 12” foot.

It is interesting to note that Sir Isaac Newton had a great interest in the length of the cubit.  His interest it seems was based upon his belief that the cubit and by extension the inch were relative to the astronomical measurements he needed to confirm his gravitational theories.  Isaac Newton in his Dissertation on Cubits narrowed the value of the Hebrew or “Sacred Cubit” to approximately 23-27” in length.   He used the following 7 points to arrive at his conclusion.  All values are calculated in British inches.  1 British inch = 1.0011 primitive inches.

1. By investigation of Talmudist’s and Josephus’ in reference to the Greek cubit he calculated the range of the Hebrew cubit to 24.3 – 31.24”
2. From Talmudist’s proportion to the human body 23.28 – 27.94”
3. From Josephus’ description of the pillars of the Temple 23.28 – 27.16”.
4. By calculation of a Sabbath days journey 23.28 – 27.16”
5. By Talmudist’s and Josephus’ description of the Inner Court 23.28 – 26.19”
6. By proportion to the Chaldaic and Hebrew cubit to that of the cubit of Memphis 24.83”
7. Statement of Mersennus as to a supposed copy of the “sacred cubit of the Hebrews” 24.91”

Newton’s calculations show it is very likely that the Hebrew sacred cubit was 25” .   This would agree with Petrie statements as to the Semitic origins of the 25” cubit in ancient Egypt.  This 25” cubit is  inferred  in the Egyptian record (shown in the table above) by the division of their cubit into 25 diametric units.  This division into 25 diametric units likely facilitated the conversion of the cubit  between the Egyptian and Semitic units of measure.

The use of a 25” cubit as evidenced by the 12.5” (half cubit) foot in Babylon, Europe, and the British Isles could well be explained by the Semitic migration from Mesopotamia and Egypt.    The famous Stonehenge is but a large scale representation of these relationships.  The outer stone ring as measured by Petrie gives a diameter of 1168 British inches.  Thus showing a 1/4 Aroura fits precisely inside the outer stone circle.  Contrary to popular belief today, Stonehenge was not originally designed as a place of occult religious practice.   Quite to the contrary, it showed the advanced nature and understanding of that early civilization.  They designed and built with stone a highly accurate structure showing the relationship between linear measure, plane geometry, Pi, and the solar year.  This circle of stones created a type of mammoth astronomical almanac.   This  almanac gives precise mathematical and astronomical calculations which mankind was not fully able to appreciate or understand again until our modern era, thousands of years later.

In summary then, the cubits of ancient Egypt were used as both a linear and square measure which eloquently expressed the relationship between the solar year of 365.25 days and Pi.   Both cubit measures express an advanced knowledge of mathematics and geometry as well as an awareness of advanced astronomical relationships.  It is also apparent that an additional cubit of 25” was used at times in Egyptian history during periods of Semitic influence.   The origin and basis for this cubit are not as clear.    Based on existing evidence though, it seems the 25” cubit was used in places were Semitic influence was prevalent.   This 25” cubit likely being one of the cubits used by the Hebrew people in the Biblical record.

1.  Primitive inch = 1.0011 British inches
2.  12.5” =  1 Primitive Foot
3.  25” = 1 Semitic Cubit
4.  A primitive Perch or Rod = 16 feet, each foot of 12.5”
5.  A primitive Perch or Rod was equal to 200 primitive inches
6.  A primitive Perch or Rod was  = to 8 Semitic cubits
7.  40 Perch or Rod = 1 furlong
8.  8000 primitive inches = 1 primitive furlong
9.  8 furlong = 1 mile
10. 1 mile = 64000 primitive inches
11. 320 Semitic cubits = 1 furlong
12. 2560 Semitic cubits = 1 mile

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17 thoughts on “The Ancient Origins of the Cubit

  1. Dawn Long

    Awesome mathmetical gymnastics. The ancients had no distractions as we know them today, they took pleasure in searching and fact finding, that is why there knowledge was so vast, today we take pleasure in taking pleasure, fostering self and instant gratification, thinking nothing of the past or future.

  2. Amram Shapiro

    Bill, This is a wonderful summation of a richly complex subject. What one would give to read Newton’s detailed reasoning. I know that those who try to reconstruct the Temples seek to know the measure of the cubit. You are a fascinating man. I have read Josephus but did not know one could derive measurement from his history.

    1. William Struse Post author

      Thank you Amram,

      It truly is a fascinating subject. A 25″ Hebrew cubit would really change our picture of the Temple, Noah’s Ark, Goliath etc. Here is Newton’s, Dissertation upon the Cubit

      Thank you for the kind words. I’m just a high school educated plumber trying to walk in the footsteps of giants.

      Warm Regards,

  3. Ernest Moyer

    Happiness Interrupted

    The builders of the Parthenon in Athens held the short dimension exactly equal to the length of one second of arc of the earth’s surface. They held this stylobate dimension so close to the geodetic value that modern measures have difficulty distinguishing their construction resolution. (1214.86 inches measured vs 1215.22 inches nautical.)

    This demonstrates the ancient Greeks believed the earth was a sphere, and that they knew the exact size.

    Agatharchides of Cnidus, a Greek who lived in the time of Ptolemy Philometor, said that the length of one side of the base of the Great Pyramid was equal to 1/8 minute of degree of the earth’s surface. He believed the Egyptians some 2500 years earlier also viewed the earth as a sphere, and that they also knew the exact size.

    Modern measurements give a perimeter value for the pyramid of 3022.93 feet. Double this number to obtain 6045.86 feet and compare with the 6076.08 feet of a modern Nautical Mile. The values differ by 30.22 feet or 0.5%.

    Agatharchides was doing a lot more than guessing.

    If I take a circle and divide it into 360 degree, 60 minutes, and 60 seconds I obtain 1,296,000 seconds of circumferential arc. One can obtain equivalent radian values by dividing the circle through the famous relationship: C = 2 Pi R. The value for the radius of a circle is 206,264.81 seconds of linear distance.

    This is most curious. This is the length of the Royal Egyptian Cubit in English inches multiplied by 10,000. (10,000 X 20.625 = 206,250.)

    The western unit of measure we use in modern times, the English inch, had to be defined in some ancient past that is now unknown to us. Otherwise how did 206,264.81 seconds of radial distance get so close to 206,250 inches in our linear measure?

    If I take the number of English inches in one Greek foot, as determined from modern satellite data, 12.133204, and divide it into the length of the Royal Cubit of 20.625 I obtain 1.6999. In other words, within the possible error of modern measure, the ratio of the length of the Egyptian Royal Cubit to the length of the Greek foot is a mathematically simple 1.7/1.0.

    If I use the Greek foot value of 12.1332046 inches, calculated from the WGS84 satellite data, and multiply it by 1.7, the result would be 20.6264+ inches equal to the cubit.

    A direct mathematical relationship exists between the length of the ancient Greek foot and the length of the Egyptian Royal Cubit. The two measures of length, one circular and one linear, are tied together mathematically in a manner never before recognized in western history.

    All circular measures were originally based on the definition of the number of units in the circumference of the earth.


    All linear measures were originally based on the definition of the number of units in the radius of the earth.

    These relationships are based on the English inch defined in remote antiquity.

    The phenomenon of the Royal Egyptian Cubit was buried until such time as later man would become aware of its existence. This awakening took more than five thousand years. We cannot penetrate this mystery without invoking an intelligence behind the design that led to such startling reappearance. But even more, the preservation of components that included the definition of the measure of the radius of the earth, the definition of the surface measure, and the unique measuring system of the Egyptians, could not have been accomplished without some unknown and unacknowledged power.

    At some point in time, if mankind did not first destroy himself, some human being would come along who would penetrate this mystery.

  4. Lacy

    I just finished your nonfiction book and when you made reference to the cubic feet it had me curious on your further thoughts. It made me think of a book written in 1876 of Luther Cunnings, Bible Exergenesis and the Impending Judgement. I haven’t read the whole thing. It just came up with my research on another topic. Anyway, he measures a cubit as 21 inches. When he does this, he is discussing the curtains of the tabernacle which he states is more accurately called the tent of fixed times. Anyway the measurements of the curtains when converted to feet comes out 3430 cubit feet. He goes on to explain the 7 times 7 times 70 correlation. He states that the tent of fixed times would begin at the complete dispensing of the land to the tribes. Now to this start year I am uncertain. Some say 1399 BC but I don’t think that you have Joshua alive during this time in your timeline. Well, I am no scholar. I just delight in the Word of God. I am thankful for what ever enlightenment He gives me for my eyes of understanding. I totally geeked out over your book. Thanks for sharing it. I look forward to your next book in the series. I am not much of a fiction person but I can say you have me curious about your other books. Here is the book I am referencing.

    1. William Struse Post author

      Good afternoon Lacy,

      I’ve never heard of Luther Cunnings. Sound like something that would be fun to dig deeper into. Thanks for the link.
      I can’t help but smile when reading your comments. I too get totally geeked out of YHWH’s word. I just love to explore His word and find the treasures he had hidden for us.
      I really appreciate your comments and your wonderful review on Amazon. Thanks for the encouragement!
      Warm regards,

  5. John G Gassaway MD

    Dear Lacy

    Actually, 1399 BC is not a bad date for the awarding of lots to the tribes. Joshua was a young fighting age man at the time of the Exodus. You will find a lot of dates for the Exodus but 1453 BC is the date given in the Great Pyramid passages (The Great Pyramid Decode”‘ Peter Lemesurier)/ 1399 is 54 years. Allowing Joshua to be in the range of 74 years old at the time mentioned would not be out of the ordinary at all. Moses lived 120 years.
    I am a Bible history researcher and ran across this article while researching. Hope if helps you.

  6. Raphael

    What do you think of the work of Rene Schwaller de Lubicz work ‘The Temple of Man’ and his defining of the MBG or Master Builder’s Grid?

    … and those who came before him, and those like me who would follow?

    selah v

    137 RS SSS Mezine Mystic

  7. John

    Hello Bill, I have a question and a thought regarding the length of the primitive inch that you might wish to consider, You give the difference between these measures as: (P) inch is equal to P = 1.0011” British inches whereas; in Peter Lemesurier’s book “The Great Pyramid Decoded” – he gives the marginally different value of: (P) inch is equal to P = 1.00106” British inches. I have been researching the Biblical verses of “Revelations 13” regarding the number of the beast (666). If you apply 666 to your pc’s scientific calculator you will see that the 666 factor (!) = 1.0106320568407814933908227081299e+1593 (way more accuracy than is required – but revealing all the same). At some unknown point in history was the decimal of (factor of 666) (0.0106) applied to the P inch and then divided by 10 to arrive at Peter’s solution. The question then arises as-to who would do this and why – when the original maths proved the more accurate measure? I do not suppose that this is a question that will ever produce an answer, but one wonders nevertheless! In addition to this, the square root of 666 is: 25.80697580112788031518842060 5149 or truncated to 25.8 I realize that this is almost an inch larger than your measure but even so – might this be the basis of the Sacred cubit – or mere coincidence? Do you have any thoughts on these possibilities? Regards JFK.

    1. William Struse Post author

      Hi John,

      Thanks for your fascinating thoughts. I’d never looked at it that way before. Can’t answer your question but you’ve given me something to think about. I will say I believe there is way more to the subject than most people realize.

      Your numbers remind me of a bit of info I remember reading a long time ago on the GP. The Ante Chamber is 116.26″ in length. This then makes the diagonals of the room 66.6″. Not sure that it means anything but clearly it was intentional. You might also find the following chart interesting. Again not sure it means anything but I found it an interesting exercise. GP

      1. John

        Hello Bill, I believe this is the same diagram as used in Peter Lemesurier’s book – yes?
        I do have some thoughts on the GP measures and I am absolutely certain that those you describe do have a deeper meanings – it is up to us; (anyone with insight) to fathom those meanings out – if we are able… Please let me know if my suggestions make enough sense to you that you would be willing to reconsider the P inch & cubit measures… I would not expect you to agree without your ascertaining a much deeper realization of your own and I would be fascinated to know the point by point structure of your conclusions!
        Best of luck…

        P.s. I have been considering the Earth’s Obliquity and the Arctic circle – however there are fundamental problems to overcome there – which, if corrected would overturn our current knowledge of the Earth’s equilibrial stability… a subject I would rather not delve any deeper into until my thoughts on the subject are a little more defined. Please keep in touch – I feel we have much to share with each other to our mutual benefit.
        All the best –

  8. John

    Further to my last post: I have just read the paragraph (below) in Newton’s “A Dissertation upon the Sacred Cubit of the Jews and the Cubits of the several Nations”

    The Calculation of the Ægyptian Cubit is confirmed by the present Cubit of the Ægyptians used in the city of Grand Cairo, which Mr. Greaves found to be 18241000 – 8241000 of the English Foot. This Cubit approaches nearer to the antient Cubit of Memphis, than to the lesser Cubits of the Greeks, Romans, and Arabians who reigned in Ægypt; and therefore it seems to be derived from that of Memphis.

    But it is greater than that. And what wonder is it, that a measure should be somewhat increased in the space of above 3000 years? The measures of Feet and Cubits now far exceed the proportion of human members; and yet Mr. Greaves shews from the Ægyptian monuments, that the human stature was the same above 3000 years ago, as it is now. The measures therefore are increased, the reasons of which may be assigned. The instruments, which use to be preserved as standards of measures, by contracting rust are increased. Iron beaten by the hammer may insensibly relax in a long space of time. Artificers likewise in making instruments, choose to err in the excess of the materials; and when by filing they attain any measure, which they think sufficient, they stop, knowing that they can soon correct that little excess by filing, if their master should complain of it; but that they cannot remedy a defect. Let us suppose therefore, that all measures have increased by degrees, especially in the first ages, when less care was taken of them; and the Cubit of Memphis, about the time of the Roman Empire, will be a mean between the antient and the modern Cubit, but will approach nearer to the modern.
    The antient Cubit was 17191000 – 7191000 of the English Foot, and the modern is 18241000
    8241000 of the English Foot. The mean therefore between them will be about 178100 – 78100 , or 179100
    79100 – of a Foot. Now 10000 of such mean or middle Cubits make, as they ought, about 30 Attic Stadia.

    In a nutshell Newton states that the (original) ancient cubit has steadily increased in size (and become increasingly cruder) with each subsequent occupation by invading nations. Would this not argue for the original measure of the P inch to be based on factor !666?
    Regards JFK.

  9. Mike Cooper

    Hi William,
    Thank you for the article “The Ancient Origins of the Cubit”.
    I think the following in your article “Mr. Flinders Petrie, the eminent Egyptologist, found that the 25” cubit was used in Egypt during the XVIII Dynasty. This was a period of time when the Egyptian culture was heavily influenced by Semitic culture. According to him the 25” cubit is only found during periods of Semitic influence. (see Petrie, “Hist. Egypt,” Vol. II, pp.146-153.)” is a quote from either Davidson or the Edgar brothers. Since Petrie is very antagonistic to the concept of the 25” sacred cubit, as you can see from section 153 of his “Pyramids and Temples of Giza”, I have, in times past, looked up this reference and personally I don’t agree that Petrie made any such assertion. Can you tell me why you think he did please?
    Actually I really don’t think there is such a thing as the Pyramid Inch or a sacred cubit of 25.025 British inches. The closest cubit I have been able to find is a 25.3” Persian cubit and this is somewhat less than the value that Newton eventually came up with in his dissertation, 25.6”. In my mind the Pyramid inch discredits the chronology aspect of Pyramidology. I think the cubit in the Bible is 20.607” for the reasons of pi and 365.25 that you discuss in the article and I think that the Pyramid uses this too. It is otherwise known as the Royal Egyptian Cubit (REC).
    I think the inch in the Pyramid is the British inch (“). If you look at the Figure you provided and also Petrie sections 47-52 on the Antechamber and Kings Chamber you’ll see that the distance from the south wall of the King’s Chamber to the center of the Antechamber is 365.24”. The average Antechamber length is 116.30” and both are close to what you said in the article. In Pyramid inches they are 364.84” and 116.17” which are not as close to 365.25 and 116.26 as the British inch values. I see this difference creeping in elsewhere.
    You might find these relationships interesting. Based on the 20.607” Royal Egyptian Cubit (REC) the following are true:-
    Artabic Foot (REC/√2*5/6) 12.1428”
    Remen (6/5 * Artabic Foot or REC/√2) 14.5714”
    Nippur Cubit (Remen * 7/5) 20.3999”
    Megalithic Yard ( 8/5 Nippur Cubit) 32.64”

    Notice the 6/5, 7/5 and 8/5 relationships?

    Mike Cooper

    1. William Struse Post author

      Good evening Mike,

      Thanks for your comments. Boy its been a long time since I’ve visited the subject. I checked the reference and you are correct it doesn’t mention the cubit at all as far as I can tell. I don’t remember why I used the reference. The quote you mentioned from my article, I believe is not a direct quote if I remember correctly but rather a summary of Davidson’s thoughts on the subject and is probably where I got the reference from.

      In any case it looks like I need to research the subject a bit more and correct my article. Thank you for pointing out the error. I always appreciate when readers help keep me on track, especially when done as graciously as you have. It is such a rich and facinating subject to explore. Thanks for sharing your thoughts and insigths.

      Warm regards,


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