I'm new to cake decorating and my 3rd and 4th cakes have come out great. I will be making an island/tropical theme 40th birthday cake for 50-50 people for Saturday. What did I get myself into...lol?! Anyway, I have a vision in my head for a 2 tier cake (i think...lol) but I'm not sure what size pans to use to feed that many people. Please help.

6"/8" square tiers will serve 50.

Whenever I make cakes for people I find that they want a good sized piece of cake so I usually size my cake portions according to 2X2 pieces. There are some really helpful charts on CC for both round and square cakes portions and cutting guides. Just determine what sized pieces will be served and you can go from there.

Round Cake Guide:
http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1300478

Square Cake Guide:
http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1300479

Hope this helps

Thanks so much! I really appreciate it.