I'm needing to do a cake in the shape of a six and a zero (for a big 60) for a serving size of fifty people. How on Earth do I figure up how large to make each letter? I use Earlene's cake chart for everything else, but this is a new one for me.

Thanks so much!

Although it is cupcakes, this worked very well for a 90th birthday:

http://christinascakes.shutterfly.com/pictures/319

You could make 30 extra cupcakes and arrive at 50 servings.

Thank you so much for that!! That is a great idea!! However, they have a specific cake they sent a picture of that they want it to look like. :/ I just don't know how big to make it! :p

I love your idea though!!

There is a template on this website on how to cut out numbers from a sheet cake size pan. That might give you an idea as to how many servings you'll get. If it's not enough you could always just make an additional cake and only ice it (not decorated) just for serving the rest of the guests. OR put the number cake on top of a sheet cake.
Just some ideas...

Mae_mom~~Is it possible to attach a photo of the cake picture they sent you?

Well, I would start with ovals for the 6 and the 0. The 0 you don't have to carve at all and the 6 will be losing, what, 20% of the cake? Does Earlene's chart have ovals on it? I can't give you the exact numbers because I don't use her chart. But my chart (12 cubic inch servings) says the largest oval in the wilton set (13x16"ish) x 3" deep will give you 42 servings for each cake before carving.