Biblical scholars say that Noah’s Ark measured about 300 cubits long, 50 cubits wide, and 30 cubits high. We can argue about which cubit to use but let’s say Noah used the Roman cubit which is about 0.4445 m.
That translates to an ark that measures 133.2 x 22.2 x 13.32 cubic meters. Athanasius Kircher, a German Jesuit who published Arca Noe in Tres Libros Digesta in 1675, said that the ark only has 150 kinds of birds, and roughly the same number of animals from the other vertebrate groups. This of course, did not include the fishes since they don’t need a boat, or those that arose from spontaneous generation. During the 17th century then, the animals did fit snugly in Noah’s Ark, not to mention his grinding mills.