Sheet Cake Size And Math - Rant

By beachcakes Updated 24 Oct 2007 , 5:16pm by mccorda

beachcakes Posted 24 Oct 2007 , 11:37am
post #1 of 8

Ok, first I'm warning that I'm not the best at math, so i might be off on my figures. I posted a question last nite about needing a sheet cake to feed approx. 100 for Sunday at church. In the past, they've let me do what I want creatively, but this time they need the ease of a sheet cake.

Here's my problem, and indydebi helped shed some light on my other post, but now I've done the math and I'm annoyed.

According to Wilton, a 9x13 double layer, filled sheet serves 45
a 12x18 double layer filled serves 72
I need approx. 100 - they said they could cut small and not sure how many people would actually want cake.
So, two 9x13s would put me in the ballpark. Right? Wrong!!
I got to wondering how a 13x18 would get me 90 when a 12x18 gives 72.

Well, it doesn't - here's the math for party sized slices, 1.5x2":
1 9x13 = 6.5x6 = 39 (how did they get 45?)
1 18x13 = 9x8.6= 77
That's THIRTEEN less servings!!

I guess it's my fault for not doing the math, but I really don't like math, and you would think that you could trust Wilton's sizes!

Grrr! Thanks for listening! I'm glad I did the math before I baked!

7 replies
GeminiRJ Posted 24 Oct 2007 , 11:47am
post #2 of 8

For 100 I would use (2) 12x18's. Figure about 3-4 servings per cup of batter. It'll get you in the ballpark, and then you can decide if you want to make less or more...depending on the type party it is.

chovest Posted 24 Oct 2007 , 11:57am
post #3 of 8

I don't know if this will make it easier or not. If you figure the square inches of the 12 x 18 it is 216. The square inches of a party slice (1.5 x 2) is 3. Divide 216 by 3 to get 72. HTH

amysue99 Posted 24 Oct 2007 , 12:02pm
post #4 of 8

I dont' like Wilton's chart either. Indydebi has a really great serving chart that I use all the time. It's got different numbers for party, wedding, and family size slices. I always price by the wedding slices. Ifyou do a search for Indydebi and serving chart, it will probably pop up.

As for me, when I need 100 servings, I made 2 12x18 put together.

beachcakes Posted 24 Oct 2007 , 12:23pm
post #5 of 8
Quote:
Originally Posted by chovest

I don't know if this will make it easier or not. If you figure the square inches of the 12 x 18 it is 216. The square inches of a party slice (1.5 x 2) is 3. Divide 216 by 3 to get 72. HTH

Yes, this is a much easier way of looking at it - did i mention I don't like math? Thank God for Excel!

This is for cake & coffee after Confirmation Sunday around 2:00. There are 20 kids getting Confirmed and then parents, siblings,etc. and the Bishop, Priest, Altar Servers. I think two 12x18s might be too much? I guess better too much than too little though.

Sheet cakes make me nervous to begin with - that's alot of white space!!

mccorda Posted 24 Oct 2007 , 3:16pm
post #6 of 8

A 12 x 18 single layer cut into 2x2x2" squares is 48 servings (12/2 =6 18/2 =9, 6x9=4
Put a second layer on top, and cut it into 1x2x4" slices and it feeds 96

That's the way I've always cut it.

leily Posted 24 Oct 2007 , 5:10pm
post #7 of 8
Quote:
Originally Posted by mccorda

A 12 x 18 single layer cut into 2x2x2" squares is 48 servings (12/2 =6 18/2 =9, 6x9=4
Put a second layer on top, and cut it into 1x2x4" slices and it feeds 96

That's the way I've always cut it.

I figure single layers as 2x2x2 servings and doubles as 1x2x4 like you do, but with a 12x18 I get that 6x9 = 54 so then a double layer would equal 108

mccorda Posted 24 Oct 2007 , 5:16pm
post #8 of 8

Oops , my math is off this morning!