I am about to make a large sheet cake with my new Magicline 12x18x2 pan......How many boxes of cake mix should I use?!!

I just looked in the Wilton 2006 book and it gives the following information: for a 12x18x2 you will need 14 cups batter for 1 layer 2 inches. I wish I could help you more; however, I haven't yet made a cake that large. I'm new to decorating. I'm sure someone else will see your distress call and come to the rescue.

I'd say 2.5 to 3 boxes of mix. Someone told me that you can take a measuring cup and fill it with water, put it in your pan to see how many cups it holds to give you an idea of how many cups of batter. ??? One of our CC pros may be able to help more than I.

measuring cup with water is actually a good idea !

I never would have thought of the measuring cup with water idea - it's brilliant! I have always gone by the Wilton charts, and base it on 4 cup of batter per mix (I use Duncan Hines). It usually takes fewer boxes than what I calculate, but I would rather have too much...

I have a 11 x 15 2" deep cake pan and I used 2 boxes of DH cake mix just to give you an idea. I'm new to cake decorating and this was my first big cake I baked.

I just made a cake that size and someone on here gave me great advice. You can do 2 boxes of cake mix, plus two extender recipes (found in the recipe section of this site) and it makes a perfect size cake. Someone else also suggested using four boxes of cake mix. The extender and cake mix made the cake taste homemade though, so I highly recommend it. Good luck!