What were the biblical dimensions of Noah’s Ark?

The biblical dimensions of Noah’s Ark were 300 by 50 by 30 cubits.

Genesis 6:15 gives the ark’s length as 300 cubits, its breadth as 50 cubits, and its height as 30 cubits. The measurements describe a large rectangular vessel with a length-to-width ratio of 6:1. Genesis also mentions three decks, a side door, and a window.

A cubit was an ancient unit based broadly on the length of an arm, so its exact value varied by culture and period. For that reason, modern conversions are estimates rather than an exact biblical metric specification. Using a common cubit of about 45 centimetres gives approximate dimensions of 135 by 22.5 by 13.5 metres.

The dimensions should not be confused with later artistic reconstructions or with measurements from other flood traditions. The 300:50:30 figures come specifically from the Genesis construction instructions.