A dog crate should be sized so that your dog can comfortably stand up, turn around, and lie down fully extended inside it. Specifically:

• The dog should be able to stand without their head touching the top of the crate, with about 2 to 4 inches of clearance above their head.
• The dog should be able to lie down and stretch out their limbs fully.
• The dog should be able to turn around easily inside the crate.

To determine the right size, measure your dog’s height (from the top of the head to the floor) and length (from the tip of the nose to the base of the tail, excluding the tail). Then add 2 to 4 inches to both measurements to find the minimum crate height and length needed

. A crate that is too small will make your dog uncomfortable and can cause negative associations with the crate, while a crate that is too large may reduce its effectiveness for house training, as dogs might use one corner as a bathroom

. For puppies, consider crates with adjustable dividers that can grow with your dog, so you don’t need to buy multiple crates as they grow

. In summary, the crate should be just large enough for your dog to stand, turn, and lie down comfortably, with a few extra inches of space for comfort but not so large that it encourages accidents inside.