Hi could anybody point me in the right direction (link or website) for portion sizes. When i am asked to do a cake for 40 people minimum i can only find like wedding size portions (finger thin) i would like normal sizes iykwim.

Please define "normal serving". The size you serve at home, party size, restaurant serving.

I just found this thread, maybe it will help.

http://cakecentral.com/cake-decorating-ftopict-677912.html

Here is Wilton's party & wedding servings. hth

http://www.wilton.com/cakes/making-cakes/baking-party-cake-2-inch-pans.cfm

http://www.wilton.com/cakes/making-cakes/baking-wedding-cake-2-inch-pans.cfm

You can type in your own portion sizes with Metria's cake calculator:
http://shinymetalobjects.net/cake/calculator/cake_calculator_byVolume.cgi

Keep in mind, venues will often cut to industry standard 1"x2"x4" (8 cu. in.) servings.

A "wedding" size is generally 1x2x4" (8 cubic inches) and a "party" size is generally 3x2x2" (12 cubic inches).

In my opinion, normal is wedding servings, but I hate this idea that everything food wise has to be super sized out there.

Wedding portions are a little smaller because it is assumed the cake will be served after a full meal and drinks. It is also a good serving standard for cake sizes. The standard is 1x2x4 inches as KoryAk said.

Party size is generally considered for events where cake is the only food item. Birthday parties come to mind. The standard is 1.5x2x4 inches like KoryAK said.

It is a guide that depends on what is being served at the event, not the event itself. BTW those are good sizes. Prove it to yourself by cutting a piece of foam or even a couple of slices of bread to see how big it is.

Bigger sizes are serious cake eaters and should be used to buying/paying for more.