It’s not advisable to scale a recipe based on the total capacity a pan will hold since you do not fill a pan to capacity.

A more accurate method used by baker’s is to calculate the difference in area between the two pans

First find the area of the circle for each pan

1. Radius is half the distance of a circle.

2. Square the radius (multiply the number by itself)

3. Multiple radius squared by pi

4. Pi is 3.14

Radius of 9.5” pan

9.5 ÷ 2 = 4.75

Square the radius (4.75)

4.75 x 4.75 = 22.56

Multiply radius squared by pi (3.14)

22.56 x 3.14 = 70.80

The area of the 9.5” pan is approximately 71” (70.80 rounded up is 71)

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Radius of 10” pan

10 ÷ 2 = 5

Square the radius (5)

5 x 5 = 25

Multiply radius squared by pi (3.14)

25 x 3.14 = 78.5

The area of the 10” pan is approximately 78”

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Now calculate the difference in percentage between the two pans.

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

Area of 9.5” pan = 71

Area of 10” pan = 78

78 ÷ 71 = 1.098

You need one full recipe plus an additional .10 (0.98 rounded up is 10 percent.

Since the difference between the two pans is only 10%, you do not need to adjust your recipe.

When the difference is 20% or greater, then scaling the recipe is advisable.

BTW: the only way to properly scale a recipe is if the measurements are in weight. You cannot properly scale a recipe written in volume.

Today is 3/14—which is Pi Day. Happy Pi Day!