Noah's Cubit White paper       Home   Menu




the nbr hypothesis

supporting evidences

    uniformity of the royal cubits

    royal cubit used for building

    Egyptian standard keeping


    common cubit earlier    


   structural implications    

   the space argument

    pitfalls of a dual cubit defense




Of the multiplicity of ancient cubits, which one is best for Noah's Ark? 

An exact definition might be unattainable, but several clues point to a particular range as being the most likely. Early Mediterranean cubits formed two distinct groups, so the choice is between the longer 'royal' cubits and the shorter 'common' ones. Creationist authors have been unanimous in selecting the shorter cubit for Noah' Ark (Table 1), the justification given by Henry Morris in 1976 went like this; "To be very conservative, assume the cubit to have been only 17.5 inches, the shortest of all cubits, so far as is known."  

This study highlights the limitations of the short cubit, and suggests an alternative for a more robust and defensible line of reasoning.



This study explores common cubit definitions, highlighting the possibility of the ark being larger than current estimates. Previous studies have used the short cubit to confirm there was ample room on the ark. Likewise, stability and seakeeping are also understated when using a short cubit. However, a conservative analysis of the strength and construction of the ark is exactly the opposite - the long cubit becomes the "worst case" scenario. If the timber hull of Noah's Ark had to survive heavy seas, then structural issues (such as leakage due to hull flexing) need to be assessed. If there is even a slight chance of Genesis 6:15 referring to the long cubit, then conservative structural analysis should employ this scale.  

Let's assume for a moment that the long cubit is the best choice. God then defined an ark 515 ft (157m) long. Obviously the ark should have been perfect fit, otherwise God made Noah do a whole lot of work for nothing. Now we have a problem. Woodmorappe's calculations show we can easily fit all the animals into an 18" cubit ark, but if the ark was built using a cubit closer to 21" then the space calculations are out by almost 60%. (Point 331)

The common cubit is not the most ancient. This immediately casts doubt on the common cubit as a candidate for Noah's Ark. The general consensus is that the royal cubits predate the common. Obvious similarities in the royal cubits of early post flood civilizations point to a single historical source - the Tower of Babel. The link from Babel back to Noah is a simple one, and changing the length of the cubit during this time would have been an uphill battle while everyone was working together and speaking one language. So Noah's cubit should have continued relatively intact right up to the royal building cubits of Babylon and Egypt. At the very least, the sum of arguments for using the royal cubit to define Noah's Ark is much stronger than the case for the common cubit.

Even a cursory examination shows up problems with the common cubit. For example, if we can take the longevity of the early patriachs as a clue, we should expect to see a general degradation of physical height at least in terms of population averages. However, the common cubit is a mere 18 inches (457mm) at best, corresponding to a person less than 5' 6" (1676mm) tall. This is too short for the Creationist model of pristine health and stature before the flood, especially considering Noah's cubit would have been taken from a kingly figure such as Adam, Methuselah or even Noah himself. 

Noah-Babel-Royal (NBR) hypothesis   

More than a few (non creationist) authors have put forward complicated theories for the origin of the cubit, particularly the famous Royal Egyptian cubit. Some even claim the ancients derived the length by some special ratio of the diameter of the earth. However, its very name and definition is firmly elbow-to-fingertip length, regardless of the assortment of subdivisions. The cubit was ubiquitous in ancient times. So here's a suggested explanation based on the Biblical account and the well documented tendency of construction standards to remain unchanged throughout long periods of continuous civilization. It also explains why the royal cubits appear exaggerated. (Ref 9991)

Noah built the Ark using the building cubit of his day. Regardless of whose forearm it represented the person was probably fairly important. It would be consistent with a higher view of created intelligence to expect the cubit to have been defined well before Noah came on the scene. Standardization is necessary for any serious construction project and it is unreasonable to expect the Ark was the first time the ante-diluvians had attempted to build something big. At worst, Noah used his own forearm to set the cubit length, and he was the third oldest recorded man, beating Adam's 930 year lifespan by 20 years. We would expect Noah or his even more 'important' ancestor to be somewhat tall, but not taller than a modern extreme. The reasoning is similar to the modern diversity in the canine kind, we should expect Adam to be a brilliant all-rounder but not necessarily taller than today's elite basketball players. Perhaps 6' 4" (1930mm). 

The Tower of Babel was almost certainly built using the same cubit as the Ark. Immediately after the flood Noah would have been the world's most influential figure, and he lived another 350 years. His three sons were experienced in construction and would have passed on their knowledge to later generations. The Bible clearly indicates the new civilization was staying in the one place and working together, a sure recipe for continuation of the cubit standard. Standards of measurement are not easily changed even when there is pressure to change them. In the case of the Babel construction, the pressure would have been to maintain the cubit. The chances of the Ark cubit being used in the Tower of Babel are very high indeed, since they were still acting as one people and one language. Gen 11:1

The post Babel nations took the Ark cubit with them. One of the most remarkable features of the royal cubits is their similarity. The most ancient cubits of Egypt, Babylon and Persia are almost identical, pointing to a single origin. Had the cultures developed independently we should see an early diversity of standards with a later convergence with increasing trade. However the evidence points to exactly the opposite. It appears the cubit itself lends support to the Biblical Babel dispersion as indicated in the Table of Nations of Genesis 10. The most reliable cubit of all is the Royal Egyptian cubit, well documented and cross-checked using measurements from the pyramids and all types of ancient constructions, builders marks, cubit rods and even surviving cubit standards in granite. The variation is an almost unbelievable 1/50th of an inch (0.5mm) (Ref 1).   

The common cubit became popular. The approximate cubit of everyday commerce and domestic construction was not regulated like the Egyptian royal cubit. By the time of Moses there were two distinct cubits, the common cubit now called "the cubit of man". Interestingly, Egypt, Babylon and the Hebrews all had the dual cubit definitions, common cubits around 18" and royal cubits around 21". However, Jewish scholars believe the Hebrews did not get their measurement system through Moses (i.e. Babel to Egypt to Israel) but directly from Babylon. Not only do the subdivisions of the cubit follow the Babylonian system, but other weights and measures are obviously similar. Just as we see today, the common cubit would have been an unregulated measurement and likely to drift under commercial pressure (dishonesty). Obviously this was a problem in Moses day and still an issue during Solomon's reign, as seen by the clear teaching opposing dishonest measurement standards.

Solomon may have used the royal cubit to build the temple. Solomon is recorded as the wisest man of all time (which by-the-way, means he was wiser than both Adam and Noah). This wisdom was a practical wisdom; apart from his fame as a diplomat and philosopher, he excelled as a biologist, builder, engineer, metallurgist, administrator, and it appears, an historian. When constructing the temple, 2 Chron 3:3. "...Solomon was instructed for the building of the house of God. The length by cubits after the first measure was threescore cubits..."  Since Solomon was more than capable of piecing a bit of history together, God told him (See Note 2222) to use the building cubit (the old long ones), not the everyday commercial cubit (the new corrupted ones). Solomon was smart enough to know that real building projects used the royal cubit, not the 'modern' corrupted common cubit. Since dishonest weights and measures are an abomination to the LORD (Pr 20:10), it is hardly surprising the temple should have nothing to do with it. 

The Siloam Tunnel was constructed using the common cubit - or worse.  Later, in Hezekiah's time, the short cubit was used for constructing the Siloam tunnel. Modern measurements based on the Biblical 1200 cubits indicate a length of 17.22". This is the shortest cubit listed in Table 1, corresponding to a human height of approximately 5' 4" (1626mm). Perhaps the tunnel measurement had been rounded up to sound impressive in Hezekiah's day, or maybe the common cubit continued to shrink due to the pressures of commercial dishonesty. In any case the Siloam tunnel is a poor choice for defining Noah's Ark. 

Cubits Used in Previous Ark Studies

The following table shows cubit lengths chosen by key creationist authors dealing with Noah's Ark. This table gives the impression that the 18 inch cubit is the upper limit to the cubit length, but the reasoning is clearly driven by a conservative space argument. All studies have employed the common cubit, despite the lack of evidence of its use in major building projects in the earliest civilizations - Noah's immediate descendents. 

Table 1. Cubit Length in Noah's Ark Studies. 





 Based on... 


The Genesis Flood. John C Whitcomb, Henry M Morris, R & R Publishing 1961



"While it is certainly possible that the cubit referred to in Genesis 6 was longer than 17.5 inches, we shall take this shorter cubit as the basis for our calculations"  p10


The Ark of Noah. Henry M Morris, CRSQ Vol 8, No 2, p142-144. 1971



"Assuming the cubit to be 1.5ft, which is the most likely value" p142


A Comparison of the Ark with Modern Ships; Ralph Giannone, CRSQ Vol 12, No1, p53, June 1975



"The cubit is understood to be 18 inches, which seems to be at least approximately correct,..."


The Genesis Record: Henry M Morris, Baker Book House, 1976: p181



 "To be very conservative, assume the cubit to have been only 17.5 inches, the shortest of all cubits, so far as is known."


Was Noah's Ark Stable? D H Collins, CRSQ Vol 14, No 2, Sept 1977 



From cubit list in Ramm, Bernard 1956, The Christian View of Science and Scripture. p229. Collins says.. "For present purposes I will assume the cubit equal to 18 inches"


Safety Investigation of Noah's Ark in a Seaway; S.W.Hong et al , CEN TJ 8(1)1994 (AiG)





"We adopted the common cubit...17.5 inches". After Scott R.B.Y 1959. Weights and Measures of the Bible. The Archeologist, XXII(2). Note: The actual dimensions used in the study require a unique cubit of 450mm, giving the exact figures for 13.5m depth, 22.5m breadth and 135m length.


Noah's Ark: A Feasibility Study: John Woodmorappe, ICR, 1996, p10



"All the calculations in this work involving the Ark assume a short cubit of 45.72cm."  (Wright G.R.H. 1985 Ancient Building in South Syria and Palestine, Vol 1. E'J.Brill, Leiden. p419)


The Most Amazing Ship in the History of the World; Prof. Dr. Werner Gitt, Fundamentum; 2001 p7 (German) 



Siloam tunnel measurement compared to Biblical record (Shorter than the common Hebrew cubit)


Problems with the Common Cubit

John Morris (ICR President and long-standing Noah's Ark enthusiast), stated in conversation (July 27 2004): 

"The cubit length of 17.5" to 18" was assumed in most studies because the focus had been on the ark's volume. The authors took the conservative value of cubit size and then demonstrated that even the minimum space was adequate to fit all the animals on board. However, there are reasons to think longer alternatives, such as the royal cubits of Egypt and Babylon, may be preferable. I am certainly open to a longer cubit". 

Even as early as 1961, the longer cubits were an option. In 1976, Henry Morris, in his classic book "The Genesis Record" sums it up best when he says "To be very conservative, assume the cubit to have been only 17.5 inches..." The common cubit is conservative, but is it the most likely?





Supporting Points

1. The common cubit is not the most ancient and does not appear to have any connection with Noah's Ark.

2. In the absence of an obvious choice, a structural defense must use the longest potential cubit.

3. If the royal cubit is the best estimate for the Ark then current space calculations are off by 60%

4. Opposing constraints of structure vs space suggests a multiple solution (proof in each case), but the divine source of Noah's specifications suggest a perfect fit. 

5. The shortening of the unregulated common cubit may have been due to commercial deflation. (Dishonest scales). 



No basis for the Common Cubit predatnig the Royal  

The evolutionary minded historian (including the authors of many Bible encyclopedias) attempt to paint a picture of civilization developing from crude beginnings. Since the royal or building cubits are obviously superior to the common cubit, they sometimes imply the ancients came up with the longer cubit at a later date. (See note 5555) Trouble is, they don't have a later date, nor any indication of its beginnings. They assume that the pressures of ever increasing technology forced the shorter common cubit to be abandoned in favor of the longer royal type. Trouble is, history and the Bible point to the common cubit taking over from the royal. Commentators then treat the common cubit as the anthropometric measure, and the royal cubit as a derived measure. No explanation is given as to why the building cubit was made so much longer in the first place, other than the 7 to 6 handbreath ratio. But handbreaths won't improve accuracy - all that was needed was a fixed standard. Few commentators are brave enough to postulated a rough date for the beginnings of the longer cubit standard. Chances are, there isn't one, because it goes right back to the flood. Probable too that the longer cubit is due to the continued use of an ante-diluvian cubit that came from someone taller than the average post-Babel individual. After all, the Hebrews still called both the long and short versions "cubit" (ammah) which means "mother of the arm". 

But the Bible gives the radically different view that our history really began with Noah, obviously very capable technically. So the same technology that built a huge seaworthy vessel would have continued right through to the construction the Tower of Babel. Such engineering prowess logically demands a standardized system of measurement in Noah's day, and probably well before. Since the culture directly after the flood was unified and continuous, the defined cubit would be nearly impossible to alter, so Noah's cubit would have been used on that tower. Since God dispersed the people quite suddenly by confusing their languages, we should expect to see similar cubits used for construction all over the ancient world. These building cubits are known today as the royal cubits and this is how they look.







kus 20.6" - 20.9" 522-532


arasni 20.5" - 21.4" 520-543


meh 20.64" - 20.66" 524-525

Suspiciously similar, and hopelessly inexplicable to someone believing these civilizations did not arise rapidly from the one source (Babel). There is even mention of English, Chinese and Mexico Aztec cubits within the range 20.4" to 20.9" (518 - 531mm)
















How long is a cubit?

The cubit is defined as the length from elbow to fingertip. This measurement varies with stature, the Mishna (Jewish writings) give the height of a man as 4 cubits, a ratio of 25%. Measurements taken from UK airmen (Ref 1) indicate a ratio closer to 28%.  

Ancient civilizations used a standard cubit length. For example, the pyramids of Geza were constructed using the 524mm (20.7") Royal Egyptian Cubit. This cubit has been quite accurately determined, not only from the constructions themselves, but also from actual cubit standards left behind by the ancient craftsmen. Even as early as 1877, Petrie (Ref 2) published his findings on the ancient measure, saying that "about a dozen of the actual cubit rods that are known yield 20.65 ± .01 inches". Measurements within the pyramid chambers support this figure, dimensions within the King's chamber of the Great Pyramid give a mean of  20.620 ± .004 inches. Other evidences are left by the builders themselves, "On the facade of one of the tombs at Beni Hassan there is a scratch left by the workmen at every cubit length. The cubit there is a long variety, of 20.7 to 20.8." Petrie made a detailed analysis and concluded the length of the Royal Egyptian Cubit was Here, then, by the earliest monument that is known to give the cubit, by the mean of the cubits in seven early monuments, by the mean of 28 examples of various dates and qualities, and by the mean of a dozen cubit rods, the result is always within 1/50 inch of 20.63 






Arguments for using the longer 'royal' cubit

It is considered to be the earliest cubit 

More reasonable human stature for ante-diluvians

The royal was used for building, so logically descended from the Ark 

It is virtually identical in early civilizations indicating a single origin (Noah)

Fossil record indicates everything was bigger, so we should expect people to be on the large side

Standards tend not to change so we should expect to see Noah's cubit carried through Babel and into early civilizations

Explains why the royal cubits appeared to be exaggerated to modern historians








Cubits used in previous studies

Some cubit definitions

Cubit Issues

A modern cubit

Implications of a long cubit for the Ark



Some Cubit Definitions 

(See also Cubit References)

"The actual length of the cubit varies from 18 inches to 25 inches." (Collins 1977)

Encyclopedia Britannica says the cubit was "usually equal to about 18 inches". In the case of Noah's Ark however, we are interested in the definitions of the earliest cubits - not the most common. "The probability is that the longer was the original cubit." (Easton's Bible dictionary). 

Ancient cubits varied in their level of standardization. The Royal Egyptian cubit was remarkably consistent and well defined. In Mesopotamia, cubit standards did not survive (probably due to wood construction) - so investigation is limited to clues in building proportions. Not all cubits were defined as the distance from elbow to fingertip either, and there were usually hand-width, finger width (digits) or spans subdividing the cubit. 

Ancient cubits could be classified into 2 main groups - long and short. The approximate height of the person from whom the cubit was measured is tabulated below.





 Stature (in)

 Stature (mm) 

Short Cubits

 Short Hebrew


445 mm

5' 4"

1636 mm

 Short Egyptian


447 mm

5' 5"

1646 mm



457 mm

5' 6"

1683 mm

Long Cubits

 Babylonian royal


503 mm

6' 1"

1852 mm

 Long Hebrew


518 mm

6' 3"

1907 mm

 Royal Egyptian


524 mm

6' 4"

1929 mm

 Extra Long

 Long Babylonian


610 mm

7' 4"

2246 mm

Supporting Points

1. The common cubit is not the most ancient and does not appear to have any connection with Noah's Ark.

2. A structural defense should use the longer cubit.

3. A defense of adequate space defense should use the longer cubit if it is more likely than the shorter cubit.

3. Opposing constraints of room vs structure suggests a multiple solution (proof in each case), but the divine source of Noah's specifications suggest a perfect fit. 

4. If the longer cubit turns out to be the best approximation and we can assume God specified the Ark in those units, it should not be possible to fit everything onto an ark of the common cubit. If we can then Noah was required to build an excessively large vessel, 40% larger than necessary.

5. If the long cubit is a more correct choice, the ark's cargo and number of animals might be cross-checked, especially since a good (not too tight, not too loose) fit is expected.

6. The volume of the ark is related to the third power of cubit length.

7. The necessary strength of the ark is proportional to the cubit to the power of 3.5

8. The shortening of the unregulated common cubit due to commercial deflation. (Dishonest scales). 


Is Noah's cubit too ancient to investigate?.

The cubit has disappeared today, although in some countries it was still in use until around 1960 when it was replaced by metric units. There are many examples of measurement systems lasting through the ages. In a continuous civilization, an important base-unit like length is not easily changed. Consider the effort it took to deliberately convert to the metric system. For example, the standard railroad gauge (4ft 8 1/2") is a strange choice - the same gauge that was used in the hand drawn carts of the English coal mines, that found itself in coach-building and eventually trains.. We measure angles using 90 degrees for a right angle. We have never stopped counting 7 days as a week. The origin of many measurement systems can go back centuries.

It is worth considering that Noah's cubit would have been the only unit of length immediately after the flood and that Noah's three sons were technically skilled builders. Furthermore, Noah lived for another 350 years in the new world and his son Shem was a contemporary of Abraham. Abraham lived some time in Egypt and had influence (the Pharaoh liked his wife). Noah's cubit could easily appear in these early civilizations. In fact, it is reasonable to expect Noah's cubit to dominate every culture until the Babel incident.     

The Hebrew for Cubit is "ammah", derived from mother, as in "mother unit of measure". The same word is used throughout the Old Testament as a unit of length. This could convey the idea of a measurement passed down from an ancestor, who defined the original or 'mother' cubit. Incidentally, the word for mother is common throughout many languages.

As for standards, the Egyptian cubit has survived intact in cubit standards of wood and stone, as well as in the meticulous dimensions of their architecture. For thousands of years this cubit varied less than 5%. So it is quite likely that even the actual length of Noah's cubit may have been passed down relatively intact, at least to a few civilizations.

The Long and the Short of it.

Noah's Ark landed in the middle east. The tower of Babel was almost certainly constructed in the same cubit as the ark. If dominant cultures were to travel the least distance (or even stay put), then the ancient empires most likely to have continued with Noah's cubit would probably come from Mesopotamia or its vicinity. There are hints that Babylon was built on the site of the original Babel. These cultures would still have an infrastructure that relied on this unit of measure - hence the cubit from Sumeria should be a pretty close estimate. The three ancient civilizations in this area have surprisingly similar cubit definitions - the Egyptian royal cubit more closely defined then the other units. Since the Hebrews spent 400 years in Egypt, it would be natural to assume Hebrew cubits were an inherited Egyptian measure. However, when the subdivision structure is compared, the Hebrew cubit looks more like a Babylon import.

Not that it matters much, look how similar they are; 





 Mesopotamia (Iraq)

kus 20.6" - 20.9" 522-532

 Persia (Iran-ish)

  20.5" - 21.4" 520-543


meh 20.6" 524

Known for their meticulous construction and love of mathematics, the Egyptian cubit was an accurate 20.6" (524mm). This length can be quite readily derived from the study of construction proportions - such as the chamber measurements in the Pyramids of Gezih. Better than this, actual cubit standards have been well preserved in the dry conditions. See Petrie's derivations of the royal Egyptian cubit.

In Mesopotamia, wooden "cubit rods" decay in the wet soil, so the length is obtained from buildings that were probably laid out in whole cubits. A copper standard was unearthed, but the general picture is that cubits outside of Egypt were less exact. Modern scholars find variation in these measurements due in part to the lack of reliable records, as well as the tolerance limitations of ancient construction.

Did Moses know two cubits? 

In his final speech before the Sanhedrin, Stephen described Moses as "educated in all the wisdom of the Egyptians" (Acts 7:22). Moses was obviously familiar with the Egyptian royal cubit and intelligent enough to query its origin. Probably not a Pharaoh - the short length of the typical sarcophagus attests to this. Imagine Moses as a young man completing his studies in mathematics being handed the Royal Cubit standard to calculate the area of the palace foyer. Imagine the temptation to put this famous cubit against his own arm. Surely Moses would have spotted the anomaly - this was not Pharaoh's forearm. 

For this reason, many commentators claim the Egyptian royal cubit was an exaggeration. The problem with this charge is that three different empires all exaggerate - equally. If some Pharaoh had felt the need to appear larger than life, he could at least have chosen a cubit superior to his rivals from the Persian Gulf. Worse still, the later Egyptian empire was defining a cubit slightly less than the average on the other side of the Arabian desert. A more realistic assumption would be that all these early civilizations inherited their cubit length from the one source.  

Moses, the author of both Genesis and Deuteronomy applies a different cubit definition when he writes about a contemporary measurement of the enormous bed of King Og. Not rendered in the NIV, the OKJ translation of Duet 3:11 describes the "cubit of a man" as the unit of measure used here. The giant Og, king of Bashan slept in a bed  9 cubits long. By the short cubit (18") this is 13 1/2 feet, by the long cubit almost 16 feet. (Now that IS excessive).  In the phrase "cubit of a man", the word for man is "iysh" which is usually associated with a particular man, not "adam" which is more general  - like "mankind". Moses, the obvious author/compiler of both Genesis and Deuteronomy, appears to be making a distinction between the old cubit and the cubit defined by typical forearm length of his day. From Moses' point of view, Genesis was history, but Deuteronomy was current news "is it not in Rabbath of the children of the Ammon? Deut 3:11". Moses, educated in Egypt and familiar with the Royal Egyptian cubit of 20.6" (525mm), never made such a distinction in Genesis. This indicates Genesis was measured in an ancient cubit, not by the forearm of Moses' day. Since Moses is demonstrating his awareness of two different cubits, he should have applied himself to the task of defining Noah's cubit also - perhaps with a comment like "according to the cubit of Noah". It appears he was satisfied to let the reader assume it was the "old" measure - not distinguished from the Royal Egyptian cubit. See also: Revell Bible dictionary 

Solomon knew two cubits. 

2 Chron 3:3. ...Solomon was instructed for the building of the house of God. The length by cubits after the first measure was threescore cubits...

Since Solomon was capable of piecing a bit of history together, God told him to build with the building cubit (the old long ones), not the everyday commercial cubits (the new short ones). Later, in Hezekiah's time, the short cubit was used later in Siloam tunnel (confirmed by modern measurements), so the "cubits after the first measure" must have been the other ones. Long. 


An exaggerated cubit ... Or are we getting smaller? 

Shakespeare lived in a tiny house, and the old houses of England had low doors and short beds. The English evolutionist would naturally assume our increasing stature is a part of the evolution of man. Combine this with a few small Egyptian Pharaohs and you have a tidy precept - ancient people were small. Unfortunately, this does not work in Africa where supposed 'primitive' tribesmen can average well over 6 feet. It must also ignore the impressive physique of the Pacific Islanders 'discovered' by European sailors in the previous century, and a host of other anomalies. Even today, evolutionists are surprised when an ancient human is taller then expected. 

The Bible paints a different picture. The original creation was perfect, including extreme longevity and obvious mental and physical prowess. Good health is more likely to allow a person to grow to their correct height - at least in terms of population averages. Deteriorating genetics and the startling nutritional ignorance of many ancient urban people (e.g scurvy) would go a long way to explain their short stature.

So if the ante-diluvians were taller, we would expect Noah to be tall. The Ancient cubits correspond to a person around 6ft 4" tall. This is tall, but not impossible. In fact it is far more reasonable than an antediluvian cubit of 17.5" (163cm - 5ft 4in tall), almost certainly too small for Noah.

Dimensions are not converted. 

The dimensions of the ark are 300 long, 50 wide and 30 high. These are round numbers and the proportions are excellent for ship stability and sea-keeping performance. (4) Most readers would assume these were the original numbers God gave to Noah. Assuming these figures were recorded (probably by Shem),  Moses would have compiled them into his manuscript some years later. Being well educated and alert, Moses would have been capable of converting these figures into the equivalent units of his day. 

However, the numbers do not appear to have been modified. Conversion from one cubit to another would produce ugly numbers. For example, if the original length had been 261 Royal Babylonian cubits, this would be 251 Royal Egyptian cubits. If Moses had then rounded off to give dimensions in an apparent single significant figure (3 hundreds, 5 tens, 3 tens) the error could be as high as 20% (For example; rounding off 251 to the nearest hundred adds an extra 49/251 = 19.5%, which is more than the difference between the common short and long cubits.) Worse still, if the depth had been rounded down from 34 to 30 (12%) then the L/D ratio is modified by 35%. The Hong study showed that the dimensions were optimal within 20%. In other words, rounding off to a single significant figure could force the proportions outside the optimal values. 

The most reasonable assumption would be that Moses copied (or was told) the original dimensions as exactly 300 x 50 x 30. Setting the precedent for later Jewish scholars, Moses was no doubt careful to maintain the original numbers.  

People like their kings to be tall.

The Bible gives many examples of height being revered among men. God is displeased with this tendency, and gives them a dud king that looks the part - King Saul. The fact that he looked like a king indicates that kingship was linked to tall stature.(1 Sam 9:2). Antediluvian superiority aside, Noah's cubit would likely have come from a king, and a king would most likely have been tall.

Reverence for ancestry is another common theme - especially towards the early patriarchs. It would be reasonable to assume that the owner of the forearm defining Noah's cubit was probably someone old and famous. Anyone old was probably taller, and anyone famous was probably tall. Discounting Nephilim due to their extreme ungodliness, a 20.6" cubit (6ft 4" person) is then quite a reasonable choice - simply a tall antediluvian. 

Some Jewish tradition has Noah is the realm of the giants. The cubit does not show this however, a 20.6" forearm length is a tall person - but no giant. This misconception might be explained by the deterioration of health and stature after the flood, making a 20.6" cubit seem superhuman. (e.g. Short stature of Egyptian Pharaohs).

The Bible gives some examples of height being revered among men. God is displeased with this tendency, and gives them a dud king that looks the part - King Saul. The fact that he looked like a king indicates that kingship was linked to tall stature.(1 Sam 9:2). Antediluvian superiority aside, Noah's cubit would likely have come from a king, and a king would most likely have been tall.

The cubit of modern man


Forearm Hand Length. Posterior point of the elbow - dac tylion. (Ref 2)

Procedure: With the beam caliper, measure the horizontal distance from the elbow (olecranon process) to the tip of the middle finger.

Measure your own cubit and compare results. Check if your cubit is around 28% of your height. 

The Mishna (Jewish writings) states that the height of a man is 4 cubits (25%)



Forearm functional reach + hand length. Anthropometric data for British military (UK airmen) is freely available (Ref 3). A direct cubit was not measured, but can be derived from the functional forearm reach (21) and the hand correction factors (33 & 34), where a cubit = 21 + 33 - 34 

1987 Measurements for UK aircrew



3rd percentile

50th percentile

97th percentile



1658 1783 1901


390 424 462

grip correction - ext

178 195 212

grip correction - clasp

107 117 127

21 + 33 - 34

461 502 547

cubit % of stature

27.80% 28.15% 28.77%

The mid-sized person flying planes in the UK had a cubit of 502mm (19.8"). UK airmen were approx 1.5% taller than the US army measurements of 1988, dropping to a 1% advantage in the more competitive 97th percentile. So these servicemen were slightly taller than normal. "Clinical normality" in height is defined as about the range 54"-79". The average stature worldwide is 1650mm ´ 80mm (64.96" ´ 3.15") for men and 60.5" ´ 2.95" for women. (Ref 5). 

Considering Noah was only 10 generations from Adam and got the bronze medal in the longevity records, it would be safe to assume he was a lot healthier (and taller) than the average male on the planet today, or in the UK air force for that matter. Yet a cubit of only 457mm (18") cubit corresponds to 28% of a mere 1632mm (64.25") stature, well below the world average today. The picture is even more grim and Noah becomes vertically challenged if the 25% Mishna rule is applied. In any case a longer cubit would be a more realistic choice.

The longer measures such as the Nippur cubit or the Royal Egyptian cubit are a better match to archeological evidence, and to the Biblical framework of a creation in bondage to decay. (Romans 8:21). A structural study of Noah's Ark should take the more realistic long cubits into consideration.   


Implications of a long cubit for the ark.

One reason to prefer the shorter cubit is that it defines a conservatively small ark. This is the best way to defend the ark against accusations of insufficient space - "How could all those animals fit on the ark". Space requirements have been documented by John Woodmorappe in "Noah's Ark: A Feasibility Study". Using the 18" cubit (p50), he concludes that the animals would require only half the floor space - and this is without putting cages one above the other (p16). There is 15 feet between floors which is ample headroom. 

However, when making a case for the structural integrity of the ark, the long cubit should be used. Whenever the forces on an object are mass-related, the stresses increase in proportion to scale. This defines a maximum size limit to buildings, bridges, aircraft and machines. The larger the vessel, the more critical the structure. For example, the bending load applied by waves is considered to be proportional to the length of the vessel to the power of 3.5. See Wave Bending Moment


Stress increases with Size

Consider a rectangular beam (BxD) cantilevered over a length (L), supporting its own weight (W);

Stress = 3 x W x L / (B x D2).

If you double the scale, you will double all the dimensions, which will increase the weight 8 times.  

So Stress = 3 * 8W * 2L / (2B * (2D)2 ) = 6WL/(BD2), which means stress has also doubled. 


Generally speaking, as scale increases mass related forces (like weight) increase by scale3, but the cross-sectional area only increases by scale2. Since Stress = Force / Area, the stress increases by scale3/scale3, or scale1 - i.e. Stress is proportional to scale.

Therefore, larger structures need to be more stout. Thus a dinosaur is heavy boned, yet a spider can have whisker thin legs. A flea can leap a hundred times its own size, but an elephant can barely get off the ground. A small gymnast has an advantage, a cat can fall out of a tree and walk away, and Tyrannosaurus Rex was probably rather clumsy. So the fact that an ant can carry seven times its own weight is not so amazing after all. 

In engineering, the same applies to boats, buildings and planes. Have you noticed how we haven't really made things much bigger than we did 30 years ago? We can't unless we find a material that is many times stronger than what we had before.

Assuming sufficient wave size (probably a reasonable assumption), a longer cubit makes structural strength a more significant issue for the ark.  


Large size demands a stout structure.

We need to keep the stress within safe limits, so any increases in size must have a corresponding increase in the stoutness of structural elements.

In the previous example we wanted to double the length of the beam. This requires a 4 fold increase in breadth and depth, increasing the section modulus 64 times, but the mass only 32 times - thereby maintain the same level of stress. 

So building a larger ark is not simply a case of scaling everything up. The increase in length requires a even greater increase in breadth and depth of the structural beams. This obviously results in a maximum size for the vessel - when you end up with a structure of solid wood. 

All wood and no rooms!


So how does this effect the ark? The table below shows what happens when you increase the size of the cubit. This assumes a draft of 15 cubits (half the depth) which could be interpreted from the account of the floodwater being more than 15 cubits above the mountain tops. (Indicating that the ark could not run aground) Gen 7:20. Though not conclusively fictitious, the Babylonian long cubit of 24" is less likely because it did not appear in multiple empires - the best indication of prior date. (especially prior Babel dispersion).

Selecting the most likely cubit is no trivial matter, the mass of the ark could increase at least 50%.   






Ark Length


 % Increase

Short Cubits

 Short Hebrew

17.5" 445 133m 20255 100 %

 Short Egyptian

17.6" 447 134m 20604 102 %


18" 457 137m 22041 109 %
Long Cubits

 Babylonian royal

19.8" 503 151m 29336 145 %

 Long Hebrew

20.4" 518 155m 32085 158 %

 Royal Egyptian

20.6" 524 157m 33279 164 %
 Extra Long

 Long Babylonian

24" 610 183m 52245 258 %


Factors that could require increased strength of the hull include hull shape, large wave size, uneven load distribution on the ark, high wind speed, minimal deflection to prevent leakage, collisions with floating debris, launching and beaching loads.  

One factor that eases structural requirements is the short working life of the ark. Although the occupants may have been confined to the ark for over a year, the voyage itself lasted only 5 months. (or even less if the ark was launched near the end of the 40 days) 

See also Cubit References


References and notes

9991. The Royal Egyptian cubit too big for Pharaoh? Ubiquitous courtier     

2222. The plans for the temple were divinely revealed to David, who passed it on to his son Solomon. (1 Chron 28) "11 Then David gave his son Solomon the plans for the vestibule, its houses, its treasuries, its upper chambers, its inner chambers, and the place of the mercy seat; 12 and the plans for all that he had by the Spirit, of the courts of the house of the LORD, of all the chambers all around, of the treasuries of the house of God, and of the treasuries for the dedicated things;" NKJV.  It could be argued that David knew about the former cubit also - the royal cubit.

3333. The Jewish The author picks up the "cubit after the first measure" from Solomon's temple and links it to the seven handbreadth cubit of Ezekiel. The common cubit was typically defined as six handbreadths, the royal cubit as seven - exactly as it was in Egypt. Note: "ell" means cubit. "The Old Testament mentions two ells of different size. Ezekiel implies that in his measurement of the Temple the ell was equal to a "cubit and a handbreadth" (Eze 40:5, 43:13)—that is, one handbreadth larger than the ell commonly used in his time. Since among all peoples the ell measured 6 handbreadths, the proportion of Ezekiel's ell to the others was as 7 to 6. The fact that Ezekiel measured the Temple by a special ell is comprehensible and significant only on the assumption that this ell was the standard of measurement of the old Temple of Solomon as well. This is confirmed by the statement of the Chronicler that the Temple of Solomon was built according to "cubits after the first measure" (II Chron. iii. 3), implying that a larger ell was used at first, and that this was supplanted in the course of time by a smaller one."

4444. The International Standard Bible Encyclopedia. "The standard for measures of length among the Hebrews. They derived it from the Babylonians, but a similar measure was used in Egypt... The Babylonians early adopted a .... double standard, the so-called royal cubit and the ordinary one. From the remains of buildings in Assyria and Babylonia, the former is made out to be about 20,6 inches, and a cubit of similar length was used in Egypt and must have been known to the Hebrews. This was probably the cubit mentioned by Ezekiel 40:5 and perhaps that of Solomon's temple, "cubits after the first measure" (2 Chronicles 3:3), i.e. the ancient cubit. The ordinary cubit of commerce was shorter, and has been variously estimated at between 16 and 18 or more inches, but the evidence of the Siloam inscription and of the tombs in Palestine seems to indicate 17,6 inches as the average length. 

5555. The International Standard Bible Encyclopedia. The original cubit was the length of the forearm, from the elbow to the end of the middle finger, as is implied from the derivation of the word in Hebrew and in Latin (cubitum). It seems to be referred to also in Deuteronomy 3:11: "after the cubit of a man." But this was too indefinite for a scientific standard, and the Babylonians early adopted a more accurate method of measurement which passed to the nations of the West.

1. The Genesis Record; Henry M Morris, Baker Books, 1976

2. National Biodynamics Laboratory

3. 1988 Anthropometric Survey of U.S. Army Personnel: Methods and Summary Statistics - a technical report (NATICK/TR-89/044) authored by Claire C.Gordon, Thomas Churchill, Charles Clauser, Bruce Bradmiller, John McConville, Ilse Tebbetts, and Robert Walker Wendy Murray

4. Ministry of Defense.(00-25 Part 2) Human Factors for Designers of Equipment Part 2: Body Size. Feb 1997

5. Anthropometrics and Design. Lecture notes.




What is the most likely length for the cubit of Noah's Ark?

The cubit is normally defined as the length from elbow to fingertip, but how long was the arm?  

(See also Cubit References)




Main points

1. A cubit length of 18 inches is unlikely.

2. A longer cubit makes the ark more difficult to build.

3. A shorter cubit makes it more difficult to fit everything in.

3. Opposing constraints of room vs structure suggests a multiple solution (proof in each case), but the divine source of Noah's specifications suggest a perfect fit. 

4. If the longer cubit turns out to be the best approximation and we can assume God specified the Ark in those units, it should not be possible to fit everything onto an ark of the common cubit. If we can then Noah was required to build an excessively large vessel, 40% larger than necessary.

5. If the long cubit is a more correct choice, the ark's cargo and number of animals might be cross-checked, especially since a good (not too tight, not too loose) fit is expected.

6. The volume of the ark is related to the third power of cubit length.

7. The necessary strength of the ark is proportional to the cubit to the power of 3.5

8. The shortening of the unregulated common cubit due to commercial deflation. (Dishonest scales). 



Noah's cubit. How long should it be?

Putting aside various arguments against the Ark's feasibility.


Summary of major arguments against the Ark's feasibility,  

1. How can all the animals fit?

2. The ark is too big for a wooden vessel

3. How could they take care of all the animals?

4. How could ancient people build such a serious vessel?


Virtually all objections relating to the ship itself fall into the following categories;

The ark is too small - how to fit animals, 

The ark is too big - too big for wood, too big for ancient people, 


So skeptics claim the ark is too big for wood yet too small to fit all the animals. Obviously this is not the right question to address.


What is the right question?


Since it is not the skeptic that drives our agenda, but the Word of God, the thing to aim for is; 

What is the most accurate cubit length we can determine?

If we can define a certain length as being more probable than others, then this should be the one we take. After this we can test the effects on space and construction.  






Dishonest measurement standards

Le 19:36 ‘You shall have honest scales, honest weights, an honest ephah, and an honest hin: I am the LORD your God, who brought you out of the land of Egypt.

De 25:13 "You shall not have in your bag differing weights, a heavy and a light.

Pr 16:11 Honest weights and scales are the LORD’S; All the weights in the bag are His work.

Pr 20:10 Diverse weights and diverse measures, They are both alike, an abomination to the LORD.

Pr 20:23 Diverse weights are an abomination to the LORD, And dishonest scales are not good.

Mic 6:11 Shall I count pure those with the wicked scales, And with the bag of deceitful weights?


Ge 11:1 Now the whole earth had one language and one speech.


Examples of construction and building standards that stood the test of time.

The Royal Egyptian Cubit

The slow transfer of US to metric

The continuation of archaic railway gauge

Extremely long life of cubit, foot, inch

Infrastucture inertia - shipbuilding, aircraft, brickmaking etc unchanged by metric system