How to Alter Cake Size

[SHA]

I have a cake recipe that yields 3 layers of cake 1/4 in height each when baked in a 10 inch cake pan. If I bake the same recipe in a 9 inch cake pan, would I get a fourth layer that's also 1/4 inch ? How do you figure these things out ?

 

[Norcalbaker59]

I have a cake recipe that yields 3 layers of cake 1/4 in height each when baked in a 10 inch cake pan. If I bake the same recipe in a 9 inch cake pan, would I get a fourth layer that's also 1/4 inch ? How do you figure these things out ?

No — if you divide the batter into four 9” round cake pans, each pan will have less batter than needed to produce even a 1/4” high layer.

To scale a recipe up or down accurately, the recipe must be written in metric weights (grams), not volume.

How to Scale a Recipe by Pan Size


Step 1: Calculate the Area of Each Pan

Use the formula for the area of a circle:

Area = π × r²
(π ≈ 3.14, and r is half the diameter)

• 9” round pan
  Radius = 9 ÷ 2 = 4.5 inches
  Area = 3.14 × (4.5)² = 3.14 × 20.25 = 63.58 in²
• 10” round pan
  Radius = 10 ÷ 2 = 5 inches
  Area = 3.14 × (5)² = 3.14 × 25 = 78.5 in²

Step 2: Scale the Recipe

To scale up (e.g. from a 9” pan to a 10” pan):

Divide the area of the larger pan by the area of the smaller pan:

78.5 ÷ 63.58 = 1.234

Multiply each ingredient weight by 1.234 to scale up for a 10” pan.



To scale down (e.g. from a 10” pan to a 9” pan):


Divide the area of the smaller pan by the area of the larger pan:


63.58 ÷ 78.5 = 0.8099


Multiply each ingredient weight by 0.8099 to scale down.

Example:

Original recipe calls for 355 g flour, scaled down to a 9” pan:


355 × 0.8099 = 287.52 g → Use 287 g flour


Scaling for Multiple Layers

If you want to bake a four-layer cake using 9” pans:

1. Scale the recipe down from a 10” to a 9” pan (multiply by 0.8099).
2. Calculate total batter weight for one layer in a 9” pan.
3. Multiply by 4 for four layers.
4. If your original recipe was for three layers, you’ll need to increase total batter by 1/3 (multiply by 4 ÷ 3 ≈ 1.333).
5. Apply this final scaling factor to the adjusted ingredient weights.

Alternatively, Baker’s Percentages can be used to scale batter/dough amounts. but without a recipe in metric weight, it’s impossible to calculate the Baker’s Percentages.

 

[SHA]

Thanks, based on this method, it looks like I can definitely use an 8 in cake pan for 4 layers.