I've read somewhere that Nirn is half as big as Earth?

But something I find odd is that, Tes: II Daggerfall is supposed to be 62,000sq miles, but on the map of Tamriel, Daggerfall is tiny compared to Cyrodiil,which Bethesda said is 16 sq miles....lolwut?

.....So, looking at the map of Nirn, shouldn't it be only 500 ish square miles? That is a TINY planet, unless theres lots of undiscovered continents left on it.

Where do you find a map of Nirn? All I've seen is Tamriel (the continent). Which seems to be a sort of mashup of Europe with a southern area akin to... well, nothing exactly, but a mix of desert and jungles.

The ingame Cyrodiil is 16 square miles in Oblivion, not in actuality. It's merely a restriction based on the technology. Ingame Skyrim is also 16 square miles. The entirety of Tamriel is about 12 million square kilometers according to the manual of Arena.

People who have done estimates on the size of Nirn given distances from the games estimated it have a circumference of about 24,000 kilometers, making the planet about 60% of Earth's size. Plane(t)s in TES are technically impossible spheres of infinite size and mass however, given shape by mortal mental stress.

Also, I'm sure there's plenty undiscovered. We know of three other continents besides Tamriel that remain mysterious - Atmora, Akavir, and (I guess now defunct) Yokuda.

@ Korr
Theres a picture of Nirn in Daggerfall.