I really don't know for sure. Some xxs fits really well and sometimes it is too big, and I kind of want something that he will be able to wear when he is bigger too. He is just a puppy still. It's kind of hard to tell without seeing it in person.
I mainly want something for after bath, while he is still drying. I do blow dry, but I still like to keep him warm after his dry, because his face is sometimes still damp.