I just did the math using the dimensions I gave in the instructions and it did indeed come up short. I remeasured the actual cage's interior space because I was certain I triple checked the inner dimensions before I built it. It seems I wrote down the measurement of 2 of the boards wrong. 2 of the boards are supposed to be cut at 3'4" (not 2'8". I have fixed the lengths on the building instructions page.
The inside space is 1296 sq inches. A 2x3 C&C cage is 1107 sq inches. It's above the minimum for 2 pigs and is room enough for a house rabbit to have space to stretch out when it wants to be in it's cage.
I don't recommend a cage this small for a cage kept rabbit but it's fine for a house rabbit or for 1-2 guinea pigs.
