I am doing a groom's cake for a wedding in July and was wondering if there was a rule about serving size. Like 1in. per person??

I think the serving size depends on how many layers thick the cake is. The standard Wedding cake size is 1 in. x 2 in. by two layers high (about 4 in) according to Wilton's website.

I believe the same is true for the grooms cake.

depends, are you making an armidillo with red cake. I saw that on steel magnolias. I really liked that cake., and that movie.


reapergrrl

All my cakes (except sheet cakes) are 4" high and the servings are 3"x1"x4" no matter what the cake is for. Others do a smaller serving. It's really up to you.