Genesis gives Noah’s Ark a length of 300 cubits. The same passage describes the vessel as 50 cubits wide and 30 cubits high, making the three dimensions a commonly cited biblical specification.
A cubit was an ancient unit based roughly on the length of a forearm, so its modern equivalent is not fixed. Depending on the historical cubit used, 300 cubits is often estimated at roughly 135 to 150 metres, or about 450 to 500 feet.
The measurements appear in Genesis 6:15, where God instructs Noah how to build the ark. They describe a large rectangular vessel rather than a conventional ship designed for speed or steering. Genesis says the ark was made from “gopher wood” and coated with pitch to make it watertight.