PORTIONS 

A standard 2 tiered cake would serve 45 portions
A standard 3 tiered cake would serve 80 portions
A standard 4 tiered cake would serve 160 portions

When designing your dream wedding cake, I am more concerned about the design and visual asthetics of the cake, rather than how many tiers it has. Some designs look the most striking as smaller cakes, and in this case, portions can be made up with a kitchen cake to ensure all your guests get to try delicious cake.