I use wilton's serving chart for a guide. Here is the link at the bottom they have links to 2" and 3" deep pans and wedding and party servings.
HTH
http://www.wilton.com/cake/cakeprep/baking/times/index.cfm
But to answer your question according to the chart it comes up to about 61 servings for two single layers of your cake sizes.
I think the Wilton serving chart is WAY too small!!!
For example, the Wilton chart says an 8" serves 20. No way, no how! No one actually cuts pieces that small -- they will run out of cake with only about 1/2 the people served! (I say an 8" serves 12).
Also, I NEVER do single layer round cakes, they are always two layers, so they are approx 4" high.
Anyway, 14" round serves 40.
I don't do the 11x15 pans. I do quarter sheets (9x13...15 servings) and half sheets (12x18...30 servings) and full sheets (18x24...60 servings).
Hope this helps!
Earlene's is a little more realistic I think.....
http://www.earlenescakes.com/ckserchart.htm
I'm not sure about the Wilton numbers, as I've NEVER gotten 20 pieces from a round cake. I just did four 12x18 cakes that I scored into 54 pieces. They came out to about 2x2x2 which isn't a super small piece IMO.
Quote by @%username% on %date%
%body%