Where can I go to find out how much fondant I will need to cover my cake? I ask this because I only have a bout 1.5 lbs of white fondant, and I need to know if it will cover the center tier of a topsy turvy cake I'm making so I don't have to go out and buy some more. I don't know how big the tier is going to be yet, so I'm just needing some conversion rates. Can anybody help?

Globalsugar Art has a fondant calculator:
http://www.globalsugarart.com/?id=24

Im getting into cakes that do not fall under the GSA scale... like for instance I have a cake that will be roughly a 9x13 cake that is 15 inches tall...how would you go figuring that one out?

Anyone have a calculator or trick to judging cakes that are not in your standard sizes?

The chart tells you that a 9x13 that is 2" high needs 40oz. Therefore your cake is just under 8 times bigger so just do the sum
8 x 40 which is 320oz

Sorted

Stupid question I'm sure, Math and I are not friends ... but would it be considered 8ish times more? You are only adding for the extra hight... and not necessarily the amount of fondant to cover the 9x13 "top" area for each multiplication? Does that make sense?

Yes that's true I didnt think of that, very stupid of me

Ok, so my husband helped me figure it out if anyone wants to confirm the math. He figured out the oz per square inch based on the chart, and then multiplied that by the size of my cake. The chart says a 16" square that is 4" high needs 120oz of fondont, so:

120/((16*16)+((16*4)*4))=.234375 oz per square inch

My cake is 9x13 and 15 high, so:

((9*13)+((9*15)*2)+((13*15*2)*.234375=~182 oz

The interesting part is the chart seems to require more fondant per square inch the smaller the cake, so this may be a tiny bit to much, but pretty close.