In Genesis, the Ark’s height was 30 cubits.
Genesis 6:15 gives three dimensions for the vessel: 300 cubits in length, 50 cubits in width, and 30 cubits in height. The cubit was an ancient unit based broadly on the length of a forearm, so its exact value varied across periods and cultures. For that reason, the biblical text provides the original measurement but not one universally agreed modern conversion.
The height is often overlooked because the Ark’s length is the most frequently quoted dimension. The three numbers together describe a long rectangular vessel rather than a small boat. Genesis also says it had a roof, rooms, and three decks.
The 30-cubit figure is distinct from the Ark’s length of 300 cubits and width of 50 cubits. Those dimensions should not be combined or converted as though the text specified modern metres.