Medium: 29“*21" medium dog bed for small dogs under 40 lbs.
Large: 35”*27” Large dog bed for medium/large dogs under 60 lbs.
X-Large: 43”*33” X large dog bed for large dogs under 90 lbs.
Each type of pets have different body size. Please select the right size bed according to the actual height and weight of the pet through the size chart.