How Long Did it Take Noah and His Sons to Build the Ark?

Let us look at the passage of Scripture that gives us a view of the problem that had caused such anguish for God. Genesis 6:3 is very revealing:

“And the LORD said, ‘My Spirit shall not strive with man forever, for he is indeed flesh; yet his days shall be one hundred and twenty years.’”

There have been two different explanations over the years about the period of 120 years, and it is worth reviewing these first.

Some believe that this period of 120 years was the maximum time that men would live in the future. Up until this time, many had lived way beyond 120 years – note that Adam lived until he was 930, Seth 912, Enosh 905, Cainan 910, Mahalalel 895, Jared 962, Enoch 365, Methuselah 969, Lamech 777 and Noah 500 (see Genesis, chapter 5). However, after the Flood we read that Noah lived a further 350 years; Shem lived until he was 600, Arphaxad 438, Salah 433, Eber 464, Peleg 239, Reu 239, Serug 230, Nahor 148, Terah 205 (all of these are shown in Genesis 11), Abraham 175, Isaac 180.

Secondly, many others believe that the 120 years was the time that God gave mankind before the Flood was to destroy everyone on the earth except the eight people who went into the ark.   If we look at the reason why this was to happen, it would appear from the context that it is not the longevity of mankind but is, more likely, to be applicable to the time humanity had before the Flood would occur. Many Bible scholars feel that God was giving mankind 120 years in which to repent of their wrong way of life, after which would come judgment for their wickedness.

As mentioned, Genesis 6:3 refers to the 120 years.   There is no Scriptural reference that God instructed Noah, at this same time, to immediately build the ark.  God made this decision at a time that was separate to the subsequent instruction to build the ark.  We read the instruction in Genesis 6:14-18:

“Make yourself an ark of gopherwood; make rooms in the ark, and cover it inside and outside with pitch.  And this is how you shall make it: The length of the ark shall be three hundred cubits, its width fifty cubits, and its height thirty cubits.  You shall make a window for the ark, and you shall finish it to a cubit from above; and set the door of the ark in its side. You shall make it with lower, second, and third decks. And behold, I Myself am bringing floodwaters on the earth, to destroy from under heaven all flesh in which is the breath of life; everything that is on the earth shall die. But I will establish My covenant with you; and you shall go into the ark—you, your sons, your wife, and your sons’ wives with you.”

Noah was told to build an ark – and for him, his sons, his wife and his sons’ wives with him to go into the ark – his sons must have been born and married at the time this instruction was made and the promise given.

Genesis, chapter 5, gives the genealogy from Adam to Noah, and in verse 32 we read that Noah was five hundred years old and begat Shem, Ham, and Japheth.  It is interesting to read of the events of Genesis 6:1-7 which took place and which caused God such anguish, and in verse 9 Noah “found grace in the eyes of the Lord” as he would not have been involved in all of the ungodly activity that made God pronounce His displeasure and condemnation in verse 3.

We read in Genesis 11:10: “This is the genealogy of Shem: Shem was 100 years old, and begot Arphaxad two years after the flood.” This leads to the conclusion that Shem was 98 years old when the flood ended, and 97 when the flood began.  In Genesis 7:11 we are told that the flood began in the 600th year of Noah’s life, meaning that he must have fathered Shem when he was 503.  We understand from Genesis 6:18 that God did not instruct Noah to build the ark until after his sons were born, and after they had wives of their own.  Let us make an assumption (which we have to do as Scripture does not give exact dates) that Noah fathered his three sons in three consecutive years which would mean that his last son would be born when he was 505 years old.

We have to make further assumptions as to the age when his sons married.   Let us say that Noah’s three sons were around 20 years old when they married; this would mean that Noah would be around 525 when God instructed him to build the ark.  Noah was 600 years old when the flood came and this would mean that the building of the ark could not have taken more than 75 years – not the 120 years that some have assumed.   In fact, this figure could be less if the assumptions made about the birth of the three sons was not as quick as calculated and the age that they married was greater than the assumed age of 20.   In fact, it is legitimate to make these assumptions because the biblical record is silent on these matters.   However, it is unmistakable that the time needed to build the ark was nowhere near the 120 years that some have assumed.

When reviewing the 120 years of Genesis 6:3, we find that this goes back to the time when Noah was 480 years old, not 500, simply because the Bible reveals that Noah was 500 when he began having sons (Genesis 5:32) but this does not mean that God could not have begun communicating earlier about what He had in mind at a later time.

In brief summary:

God must have first spoken to Noah at age 480

  1. Noah sired sons from the age of 500
  2. His three sons were married
  3. God gave the commission to Noah to build the ark for “you, your sons, your wife, and your sons’ wives with you.”
  4. Noah was 600 when he entered the ark
  5. The 120 years of God’s patience with mankind at that time ended when Noah entered the ark at age 600
  6. The maximum time that it took to build the ark would be around 75 years – or less.

This is an interesting subject, but whatever the exact time it took to build the ark, it is only of academic interest and is a non-salvational matter.   However, the story of Noah’s Ark is a warning that we can take from the historical record showing how God hates sin and the sinful ways of man.   It may not be too long now before God sends Christ back to this earth to destroy man’s sinful ways and societies once again but, this time, He will usher in the wonderful Kingdom of God.

Lead Writer: Brian Gale (United Kingdom)