How big was Noah's ark? Could the ark really have held thousands of animals? Exactly how much space did the ark actually take up? Genesis 6:15-16 provides answers to these questions:
This is how you shall make it: the length of the ark three hundred cubits, its breadth fifty cubits, and its height thirty cubits. You shall make a window for the ark, and finish it to a cubit from the top; and set the door of the ark in the side of it; you shall make it with lower, second, and third decks. (Genesis 6:15-16)In order to grasp the size of the ark, this question must be answered: How big is a cubit? The answer to this question, as might be expected, has often been debated. Some think that the cubit in this passage is about 18 inches in length. Others think that the cubit in this passage is around 22 inches in length. It's the safest option simply to make measurements with the 18 inch cubit, but it should be kept in mind that the cubit in this passage might have been larger.
Assuming that a cubit is about 18 inches in length, calculations can be made with ease. The ark was 450 feet in length, 75 feet in width, and 45 feet in height. The floor area of each of the three decks of the ark was about 33,750 square feet. Summing up the area of all three decks gives an enormous floor area of 101,250 square feet!
At 1,518,750 cubic feet, the volume of the ark was absolutely massive. To put that into perspective, Noah's ark could have held about 11,358,765 gallons of water. It's interesting to point out that if the cubit in this passage is 22 inches in length, then the volume of the ark was about 2,772,917 cubic feet, almost twice as large as the volume of the ark with the 18 inch cubit.
This passage also mentions what seems to be a trivial detail: there was a window on the ark. However, this window does play a somewhat significant role. Once the flood ended, Noah opened the window. He sent a raven out of the ark through the window once, and he sent out a dove through the window three times (Genesis 8:6-12). Thus, while the dimensions of the window are not given, it can be safely assumed that the window was at least as large as a raven or dove.
God's Ark Which Noah Built - Genesis 6:14
Noah Sends Out An Unsymbolical Dove - Genesis 8:8-12
The Coming Flood of the Pre-Flood World - Genesis 6:17
State of the World (2948 BC): Noah's Birth - Genesis 5:28
Man in the Image of Man - Genesis 5:3