How long did it take Noah to build the Ark?

“What is 120 years.”

For a long time, I thought it took Noah 120 years to build the ark. I was so sure of my belief that if I were on Jeopardy and this question was for Final Jeopardy, I would have bet all my earnings, as I penned “What is 120 years.” Growing up in church, I had heard this number based upon Genesis 6:3, where Moses writes the following:

Then the Lord said, “My Spirit will not put up with humans for such a long time, for they are only mortal flesh. In the future, their normal lifespan will be no more than 120 years.” (Genesis 6:3)

Maybe you have the same idea I had concerning the 120-year time frame for Noah’s backyard construction project based on this verse. Perhaps it was how the KJV translated the verse, or because I didn’t research the question presented in this post until later in life, when a child asked me this question during a VBS focused on Noah’s Ark by Answers in Genesis. I confidently stated that it took Noah about 120 years to build the ark. After my foolishly confident answer, a friend gently pointed out that this verse was not speaking of the countdown to the flood but the eventual lifespan of people moving forward.

My friend was right. Genesis 6:3 speaks of 120 years being the eventual time frame humans could expect to live up to, as easily seen when you read the verse without imposing what you already think the verse says.

If not 120 years, how long?

My parents taught children’s church when my brothers and I were growing up. When they taught on Noah’s Ark, they would take all of us kids outside and measure the length and width of the floating zoo. I remember thinking then that it was massive and that I could picture it in all its splendor with my vivid imagination. However, it wasn’t until the summer of 2021 when my family and I went to the Ark Encounter that I was fully hit with the magnitude of the project Noah was obedient to construct at the LORD’s direction. As I write this post, I need to complete several “construction projects” around the house that are a drop in the ocean compared to what Noah built and require fewer engineering aspects, too!

So if it didn’t take Noah 120 years to build this massive life preserver, how long did it take him? Let’s consider the following.

The Bible doesn’t claim Noah did it alone. Even though Noah and his family were the only ones who entered the ark, this doesn’t mean that Noah didn’t employ others to help him at particular or all stages of its construction. Consider the challenges Noah would have faced: constructing an enormous structure, sourcing all sorts of timber, and potentially using what we assume were Stone Age tools. Noah most likely had help with this ancient Titanic, and the Bible allows for this assumption.

Noah could have had help, and we have already reasoned why Genesis 6:3 does not provide a 120-year countdown to the flood. However, others argue that 100 years were needed to build the ark, based on Genesis 5:32.

After Noah was 500 years old, he became the father of Shem, Ham, and Japheth. (Genesis 5:32)

Genesis 5:32 states that Noah was 500 years old when he had Shem, Ham, and Japheth, and the flood occurred when he was 600 years old, providing a 100-year timeframe. However, Genesis 6:18 adds complexity to this timeline, as God tells Noah that he, his sons, his wife, and his sons’ wives would enter the Ark. This indicates that his sons were already grown and married by the time of this command, suggesting that the actual time Noah had to build the Ark was less than 100 years.

But I will confirm my covenant with you. So enter the boat—you and your wife and your sons and their wives. (Genesis 6:18)

Noah likely had between 50 and 75 years to build the Ark, considering the time required for his sons to be born, grow, and marry—an estimated 25 to 50 years within the 100-year window before the flood. However, it may have taken even less time.

Now I know how long it took Noah to build the ark, but could he have built a boat that size?

Some skeptics doubt how Noah could have accomplished this with primitive tools. Yet, Genesis 4:22 references Tubal-Cain, an expert in working with bronze and iron, suggesting that metal tools were available.

Lamech’s other wife, Zillah, gave birth to a son named Tubal-cain. He became an expert in forging tools of bronze and iron. Tubal-cain had a sister named Naamah. (Genesis 4:22)

Constructing such a massive wooden vessel posed significant challenges. Over decades, wood could warp or decay before completion. However, gopher wood or the pitch used to seal the Ark may have provided durability and protection against deterioration.

Skeptics also question whether one man could build something so large. The Bible does not state that Noah worked alone. Hebrews 11:7 highlights Noah’s faith in preparing the Ark but does not imply he was its sole builder. Like Solomon, who “built” the temple by overseeing its construction, Noah likely directed the building of the Ark. His three sons and their wives assisted, bringing the workforce to at least eight people. It’s also possible that extended family or hired labor contributed.

For perspective, a modern replica of the Ark took approximately two years to construct using heavy machinery and large crews. Though Noah’s methods differed, building a vessel capable of housing all the animals within several decades remains feasible.

What am I to do with this information today?

As believers, we are called to give a reason or defense for why we believe what we believe (1 Peter 3:15). I pray this post will help you to give someone a reason for why you believe the Bible to be accurate and that like the ark provided an escape from God’s judgment, Christ is our ark today for all who would enter into a relationship with Him! Secondly, may we, like Noah, have the faith in God’s Word and do what He tells us to do, even if the task seems humanly impossible, remembering that with God, all things are possible (Matthew 19:26; Philippians 4:13)!

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