I already owned a 28 x 21 x 22 airline crate for my cat. (He's a big boy.) This is what we used when we brought Galen home and when we took him to his first couple vet appointments. He outgrew the cat carrier within a few weeks. We then started using a 36 inch wire crate given to us by a friend. He outgrew that by 5 months. We now use a 42 inch crate when we are tight for space or a 48 inch crate where we have the room. Galen is currently 24" tall. Pogo was several inches taller and did not fit in a 42" crate.
FYI be careful when buying anything based on the dog's weight. Manufacturers tend to gear their sizing to broad dogs with medium legs: beagles, cocker spaniels, labradors, put bulls, and so forth. Poodles run tall, leggy, and narrow.