In Genesis, what unit is used to give the Ark's dimensions?

In Genesis, the Ark's dimensions are given in cubits.

Genesis 6:15 specifies the Ark as 300 cubits long, 50 cubits wide, and 30 cubits high. A cubit was an ancient unit traditionally based on the length of a forearm, from the elbow to the fingertips. Its exact historical length varied by culture and period, so converting the Ark's measurements into modern units requires an assumption.

Using a commonly cited cubit of about 45 centimetres gives approximate dimensions of 135 metres long, 22.5 metres wide, and 13.5 metres high. Those figures are estimates rather than measurements stated directly by Genesis.

The dimensions produce a long, boxlike vessel with a length-to-width ratio of 6:1. Modern replicas and engineering studies often discuss that proportion because it could provide stability, but such analysis does not prove the historicity of the account. The answer remains “cubit,” the unit explicitly used in the biblical specification.