Sheet cake servings vary based on the size of the cake and the hostess's preference on how big to cut each slice. For example, a 2-inch deep 9-by-13-inch quarter wedding sheet cake is cut into 1-by-2-inch pieces, which yields 54 servings.
In comparison, a 2-inch deep 9-by-13-inch quarter party sheet cake that is cut into 2-by-2-inch pieces yields 24 servings, while the same cake that is cut into 2-by-3-inch pieces yields 18 servings.
A full-sized 2-inch deep sheet cake, which measures 16 by 24 inches, yields 192 wedding-sized servings, 96 2-by-2-inch party-sized servings or 64 2-by-3-inch party-sized servings.
The person throwing the party should consider the number of guests and how many cake slices to allow each guest when selecting a cake size.