How many cake mixes does it take to do a 1/2 sheet cake? I believe the pan is 13x18 and 2" deep. TIA

12x18 = 14 cups of batter according to wilton

(their chart: http://www.wilton.com/cake/cakeprep/baking/times/party_2inch.cfm )

so at 4 to 5.5 cups per box mix....

that would be 3 to 4 boxes of cake mix.

----
i'd probably do the 4 and use leftovers for cupcakes or small rounds that could become cakeballs

-----

and I'd probably do the extender recipe too: http://www.cakecentral.com/cake_recipe-1977-0-Cake-Mix-extender.html

with this, since it makes more, 3 mixes would be enough
-----

and I know I'd play around mix different flavors together to get a custom taste --- my fav is to mix butter recipe w/ french vanilla and use all butter for the oil and milk for the water.

I use 3 mixes and the baking strips and it works ok. 4 mixes would make a nice tall cake!

I use 2 in each, then trim the dome off and stack them, it makes the cake a bit higher, which looks nice. It's only around a dollar for each (if I get them at WalMart, not my supermarket) and that's easier for me than mixing three and dividing it in half.

I use 3 in an 11 x 15, so I would use 4 in the 13 x 18.

I use DH...3 mixes fills the 12x18" sheet just right for me!

I use three for a 12x18.. i think four would bake over the top.

I use a good portion of 3 mixes.

I just made a 12x18 cake last night and I use 4 mixes; 2white and 2 chocolate. HTH

For all of you that use 4 mixes in this pan:

Is this a 2" deep pan or is it 3" deep?
What brand of mixes are you using?

(Not trying to start anything, just curious! I use three and still have to trim the "cron" off my cakes. I figure if I used 4 DH mixes in my 2" deep pan, a good potion of the batter would be baking on the oven's floor, LOL!)

ADo you have any problems with spillage? How do you prepare the sheet pan so the cake won't stick to the pan?