You should order for only 90% of your guests. Some people will not eat the cake. So again, only order for 90% - in your case that means 12 people or one cake box mix - or one 9 inch round/square cake.
Generally it depends on how deep (how many layers) your cake is. Standard serving size of a piece of cake is 1" x 2". Also depending on how large you want to cut your slices (sensible vs generous), a 7" round cake can serve anywhere from 6-10 people.
A ten inch cake feeds about 12 people if you cut it in wedge like triangles, like a pizza. However if you go to wilton.com and look at the cutting guide, they say it feeds 38, realisticly, more like 30. That is if it is at least 2 layers. and those are uniform peices so everyone gets the same amout of cake. I like this way. it makes the cake go farther and no one eats half a piece and throws away the rest. and if people want more they can always go get another piece.
Well, honey, it depends on the depth of the pan and the brand of cake mix you're using. Typically, one box cake mix is enough for a 9-inch round pan, so for a 14-inch pan, you might need at least two or three mixes to ensure your cake is nice and tall. Just follow the instructions on the box and adjust accordingly. Happy baking, darling!
An 8 inch square cake can reasonably be divided into 4 pieces, each of which will be 4 inches square.
It depends on how large the cake is.
it should take about 2-3 cups if its 6inx6in i would make 3 just in case
About 2 boxed cake mixes.
that depends on how many slices you want.
about 1 and a half
A 9x13" cake will feed about 45 people (assuming that the cake has two layers, each layer is about 2" in height, and the slices are 1.5x2" in size).
4 boxes for a single pan