Cookie cakes come in various sizes to cater to different occasions and serving needs. Typically, they range from around 9 inches (22 cm) in diameter for smaller cookie cakes suitable for individual portions, up to approximately 18 inches (46 cm) in diameter for larger ones meant for sharing at parties or events. In terms of thickness, most cookie cakes are around half an inch (1-2 cm) thick in order to maintain a soft and chewy texture while still being sturdy enough for decoration purposes. The size of the cookie cake you choose ultimately depends on factors such as the number of people you plan to serve and your desired presentation aesthetic.