I think mine is a 42 inch. I got the 2nd largest size they had, and it's perfectly comfortable for Lucy. She can stand in it, turn around, stretch out, and all that good stuff. It fits her regular bed plus her water/food bowls. Of course, we don't even have it set up anymore because she's pretty trustworthy now, but we'll put it back up when dexter comes home, and he will use it. We do use it when we take her out of town with us, and she goes in it, no problem.