These crepe pans come in different sizes. You may even find 8-inch or 9-inch, 15-inch etc.
The ideal and the average diameter of the pan is around 10-inch. Any size below 10-inch is too small unless you just want crepes for fun.
Ideally, I would recommend looking for pans over 10-inches as I did in my product reviews. However, note that a few inches are offset by the edges of the pan.