You can use any size pans (within reason) for a cake recipe. Recipes will usually tell you what size pan to use.
The caution is to adjust the cooking times and oven temps to accommodate the different sized pans.
My SO makes a cake mix in three 6" round cake pans. Then she cuts each layer in half horizontally and makes two small three-layer cakes. She usually makes and frosts one and freezes the other three half layers for later use.
"If you want to make an apple pie from scratch, you must first create the universe." -Carl Sagan