Cake Pan Math

Have you ever seen a cake recipe that sounded scrumptious and you decided you just had to make it? Then, as you are reading the recipe (hopefully before you started baking), you notice it calls for a size of cake pan that you do not have. You do have other cake pans, though, and you wonder if you can just use those. In this Cooking Tip, I will give you some guidelines for doing just that. If you are math-averse, you may want to stop reading and just run out for the specified pan size — assuming you have storage space for one more pan! However, if you are willing to bear with just a bit of figuring, read on.

At its most basic, you want to know the capacity of your cake pan and then find another pan with the same or similar capacity. For square pans, that is pretty easy. Just multiply length by width. For example, if you have an 8-inch square pan, multiply 8X8 to get 64. For your 9X13 pan, you get 117.

For a round pan, you have to reach back to what you learned in school. Do you recall that equation Pir2? That is “Pi multiplied by the radius squared.” Oh yeah, you remember hearing that somewhere, don’t you? And, Pi is 3.14. Well, in reality it is more than that, but 3.14 will suffice for our purposes.  (If you care to read about it in-depth, here is an article from Wikipedia. Let’s do an example for a 9-inch round pan. The diameter is 9 inches, which makes the radius 4½ inches. So, we get 3.14 x 4.52 = 3.14 x 20.25 = 63.6. Round it up to 64. If you shriek at even this little bit of math, here is an online calculator that will do it for you.

Remember the capacity of the 8-in square pan? It was 64. Bingo – an easy swap for an 8-in square pan would be a 9-in round pan since they both have the same capacity. (Note: this assumes a pan depth of 2 inches.)

Let’s get a bit more complicated. If you have a recipe for a cake made in a 9×13 pan and you want to make two round layers, what do you do?

Step 1: Figure the capacity of the 9×13 inch pan. Easy – 9 X 13 = 117.
Step 2: Figure the capacity of your round pan. If it is 9-inch, we already know it is 64. Doing the same calculation for an 8-in round, you get 50.
Step 3: Divide the capacity of your bar pan (117) by 2 since you want to put the batter in two pans. That gives you 58.5, which lies in between the capacity of the two round sizes.
Step 4: Make your choice. If you divide the batter into the two 8-in pans, the batter may overflow the pans. If you use the 9-in, the layers may be shorter than you want. So, if you have never made the recipe before, the safer bet would be the 9-inch pans. If you have made the recipe before in the recommended pan size (something I would highly recommend the first time you make it), how high did it rise in that pan? If it had a high rise, you would definitely want go with the 9-inch. If, however, it really did not rise that much, you might be fine with the 8-inch.

Another option is to use an oval-shaped casserole dish although the end shape may not be what you are looking for. To do that, we need to do a bit more figuring. Let’s say you have an 8×12 inch oval dish. Measure from the center to the top – 4 inches. Then, from the center to the side – 6 inches. The equation is now 4 in X 6 in X 3.14 (pi) = 75. Compare this to the capacity in the recipe to see if it might be a viable alternative. For example, this would be too large if the recipe calls for an 8-in square pan (capacity of 64) but not too bad if it calls for a 9-in square pan (81). One caveat – most oval casserole dishes are not made of metal as cake pans are. Rather, they are usually stoneware, ceramic or glass. You might need to tweak the oven temperature and/or baking time but that is another discussion.

Do you love the look of a Bundt cake? Do you have a Bundt cake pan that you barely use? Most recipes that are to be baked in a 9×13 pan can be baked in a Bundt pan. (This only works for a standard butter/oil cake, not for sponge or angel food cakes.) For here, we look at volume rather than capacity as how would you ever calculate the capacity of a Bundt pan???

Bundt cake pans are usually 10-cup or 12-cup but this is just the actual volume you would find if you filled it with water and measured how much water you used. Since the cake will rise to fill the Bundt pan, you cannot put that much batter in the pan. What you need to know is how much batter you can actually bake in that pan. Experts tell us that for a 10-cup Bundt, the batter amount would be about 6 cups. A 12-cup Bundt pan can take up to 7¼ cups of batter.

It just so happens that a 9×13 cake is usually equal to about 6 cups of batter – an amount that would be just fine in your Bundt pan. It may not bake in the same amount of time as it would in the 9×13 pan. Just think about how much thicker the batter is in that Bundt pan. Start checking your cake at the recommended bake time but do not be surprised if you need to add up to 30% more time.

There is much more that could be said but I think the above should suffice for most of your cake baking needs.