Below is the approximate portion guide for standard depth cake (3" in height):

Cake sizeDessert Portion (0.75" x 1.5" x 3")Coffee Portion (0.75" x 0.75" x 3")
SquareRound & OtherSquareRound & Other
5"14102820
6"20153530
7"24204840
8"30256050
9"40328065
10"504010080
11"6050120100
12"7060140120
14"8070170150
16"10090200180