How much cake???????!!!!!!!!!!!

I cant believe what i have just read. Me and my mom were looking on cake sites for inspiration and came across portion size and it says from a 12" square cake is supposed to give 144 servings!!! that is a 1"square piece of cake. I'm sure when it comes to serving my wedding cake people will be given a whole lot more cake than that, that's just mean, if that was the case and you only need enough cake for guests then i would only need a 10" square cake and still have some left over, we are making the cake mostly for show as i don't want one of those little cakes that make the bride and groom look like giants when they are stood next to it i wanted it to be a focal point, and the fact that we will be making it i don't want to put in all that effort for people not to be wowed by it so do expect a bigger piece of cake than a 1"square.