i'm planning out a friends birthday cake, if i make a 15 inch round cake around 4 inch high (or more). how much people would it feed? would it feed more than 50? if portion sizes weren't very small? and what usual portion size do you take for cakes?

Here you go: Cake Baking and Serving Guide 

Wilton also has a cutting chart on their site if you need one. :)

You can always add cupcakes, and make sure the pan you get can fit in your oven!

thank you very much <3