Originally Posted by BailiasCakes
I found that Wilton's is off by a lot. A 8" round is 150.79 square inches at 3 square inches per serving, that is 16.75 servings. A 10" round is 204.20 sq. in. at 3 sq. in. / ser. = 26.18 servings
How did you come up with 3 sq inches for the size of a piece? On the Wilton chart, which is the industry standard used, a piece is 1x2x4 which is 8 cu inches. You can't really measure a cylinder or a cube in square inches, which is what a round and square cake tier is. You need to measure volume. Volume of a square is easy - length x height x width. So an 8" square 4" high cake is 8 x 4 x 8 = 256 cu in. Divide that by the 8 cu inches in an industry size piece, and you get 32 pieces which is what the Wilton chart says. Volume for a round cake is pi x radius squared x height. So, for those of us who have been out of school a while, pi = 3.14, radius = 1/2 x diameter. So for a 10" round 4" high cake the radius is 5". Thereforee the volume would be 3.14 x (5 x 5) x 4 = 314. Divide that by the 8 cu inches in the standard size piece and you get 39.25 pieces. Wilton says 38 which is taking into account the rounded "corner" pieces you get and have to compensate for.
For me, this cake would cost $275 basing it on the Wilton chart for an 8" and 10: round, and half of the 6" round or 68 pieces.[/quote]
I said square inches, not cubic, determine serving count as does Wilton : "Serving amounts are based on party-sized
portions of approximately 1.5 x 2 in. Cakes from 3 to 6 in. high" which is 3 square inches or with a 4" high cake, 12 cubic inches (wedding cakes are 1"x2").
So with your examples,
- an 8" square 4" high cake is 8 x 4 x 8 = 256 cu in. Divide that by the 12 cu inches in a party size piece, and you get 21 pieces
- a 10" round 4" high cake is 3.14 x (5 x 5) x 4 = 314. Divide that by the 12 cu inches and you get 26 pieces.
- half a 6" ball is (4/3)(3.14)(3x3x3)/2 = 56 cu in. Divide that by the 12 cu inches and you get 4.7 pieces.
I'm up to 51 servings with your cubic serving math.
I think cake prices should be based on the cake, not the serving count. I give my customers both sizes and they tell me their serving intensions before I draw up a cake.
And just because Wilton has been around, doesn't make them always right. And from what I have seen, there are more and more serving charts out there to show that.