Genesis instructs Noah’s ark to have three decks.
Genesis 6:16 describes the ark as having a lower, second, and third deck. The same verse mentions a window or opening near the top and a door in the side. These details appear within the construction instructions given before the Flood.
The three-level design is part of the biblical description of the ark’s internal arrangement. Genesis also specifies its length as 300 cubits, its width as 50 cubits, and its height as 30 cubits. Because the ancient cubit had no single universally fixed length, modern estimates of the ark’s dimensions vary.
The number of decks should not be confused with the number of people, animals, or rooms. Genesis 6:14 says to make rooms in the ark, but it does not provide a complete room count. Its explicit vertical arrangement is three decks: lower, second, and third.