It depends upon the amount of food you are going to cook in it. You can find casserole pots in various sizes ranging from 18 cm upwards to 30 cm and even bigger sizes. Smaller sizes are preferable for 3-4 serves, whereas you require the large ones for eight or more. Medium sizes of the pan are good for cooking meals for 4-6 people—for example, soups, stews, sauces and rice for a small family. We hope that this information steers you towards the right purchase.