The Genesis account specifies that Noah’s Ark was 300 cubits long. The same passage gives its width as 50 cubits and its height as 30 cubits, creating a long, rectangular vessel rather than a conventional ship shape.
A cubit was an ancient unit based approximately on the length of a forearm, but its exact value varied across cultures and periods. Using common estimates, 300 cubits would be roughly 135 metres, or 450 feet, although the precise modern conversion is uncertain.
The measurements appear in Genesis 6:15, where God gives Noah instructions for constructing the ark. The dimensions are also often compared with those of other ancient flood vessels described in Near Eastern literature.
The biblical text does not provide a modern naval blueprint, and it does not identify the exact type of cubit intended. Consequently, modern estimates of the ark’s size differ slightly even though the traditional biblical measurement is consistently given as 300 cubits.