This website will be helpful to you. This lists party sizes, but you can also search for the traditional wedding sizes as well. HTH.
http://www.wilton.com/cakes/making-cakes/baking-party-cake-2-inch-pans.cfm
http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm
This is the chart I use for all cakes, doesn't matter if it is wedding, birthday or just because. For me it is easier to stick to one chart so I can keep up with all the numbers.
A 8in round serves 24 1x2x4 servings.
A 9in round serves 32 1x2x4 servings.
A 10in round serves 38 1x2x4 servings.
Quote by @%username% on %date%
%body%