I've been reading prior posts trying to figure out what size cake I need to feed 30 people. Was thinking a 6 and 8 inch would be enough. But depending which chart you use, they seem to all result in different amounts. So I guess my question is how much do you think a 6,8 inch would serve, what about an 8,10 inch?
Thanks in advance for any help

I use these charts and they are perfect.

http://cakecentral.com/articles/74/cake-baking-cutting-serving-guide-2-in-deep-pans
http://cakecentral.com/articles/75/cake-baking-cutting-serving-guide-3-in-deep-pans

If you are using round 2" deep pans = 6" serves 12, 8" serves 24, 10" serves 38

6&8 are more than sufficient - 36 servings there.

I use Earlene's serving chart since I don't do wedding cakes, and my customers usually like a slightly larger piece of cake than your typical "wedding size". I get 15 servings from an 8" round, and 8 servings from a 6" round. HTH

Here's the link for Earlene's chart:
http://www.earlenescakes.com/ckserchart.htm

It helps if you also give the customers a cake cutting guide so they can see how many pieces the cake is supposed to serve. If they want bigger slices then they need to order (and pay for) more cake.

I find it helpful to describe a slice of cake to be the size of a folded over peanut butter sandwich. I think it was Indydebi who suggested that and everyone I tell that to appreciates the analogy.

Thank you all for the responses. I will definitely go with the 6,8 inch then. I was getting a bit confused especially why Earlenes chart shows much fewer servings.

A normal serving size is 2 inches x 2 inches x 2 inches or 1 inch x 2 inches x 4 inches; both equal to 8 cubic inches of cake.