According to Genesis, Noah’s Ark was 50 cubits wide.
Genesis 6:15 gives the Ark’s three principal dimensions: 300 cubits long, 50 cubits wide, and 30 cubits high. The width is therefore one-sixth of the stated length, while the height is one-tenth of the length. These proportions are frequently used in discussions of the vessel’s theoretical stability and capacity.
Because the cubit was an ancient unit whose length varied, converting 50 cubits into metres or feet requires an assumption. Common estimates place it at roughly 22 to 23 metres, but the biblical passage itself does not define the cubit in modern units.
The width should not be confused with the Ark’s height or with the number of decks. Genesis separately describes three levels, a door, and a window, without supplying a detailed construction diagram or specifying the exact cubit standard.