What size dog crate do I need?

Most manufacturers, including MidWest, size by dog weight: 24" for under 25 lbs, 30" for 21–40 lbs, 36" for 41–70 lbs, 42" for 71–90 lbs, and 48" for 90+ lb breeds like Great Danes. Your dog should be able to stand without ducking and turn around comfortably. For puppies, buy the adult size and use a divider panel to shrink the usable space during housetraining.