According to Genesis, the Ark’s window was one cubit in size.
Genesis 6:16 includes the instruction to make a window for the Ark and says to finish it “to a cubit” or “one cubit,” depending on translation. The verse places this detail alongside directions for the door and the three decks. It does not clearly explain whether the measurement refers to the window’s height, width, or another dimension.
This wording creates a translation and interpretation issue. Hebrew versions use a phrase commonly rendered as one cubit, but the precise architectural meaning is not fully specified. Some translations describe a skylight or opening rather than a conventional vertical window. Consequently, the biblical number is clear while the exact shape and placement remain debated.
The window later becomes significant in the narrative because Noah opens it before sending out birds. That later scene does not supply additional dimensions. The safest answer is therefore the textual measurement, one cubit, rather than a modern reconstruction of the opening.