Thank you for your question. Before you select a cage, you must measure your pet to be sure you select the right size. Measure from the floor to the top of your pet's shoulder, and add 3 inches; this is the minimum height for your pet's cage. Next, measure from his head to the base of his tail, and add 3 inches; this is the minimum length for his cage. Make sure that your pet can comfortably stand, sit, turn around, and lie down in it. You can always add a divider panel if necessary, and reserve the remaining space until your pet grows into it. As a general rule, when selecting a cage for an adult dog, if you're not sure which size to select, lean toward a larger size.