mudd
February 10, 2020

Easy way to consider this issue-surface area only. But need to also consider capacity/volume. Eg recipe calls for 8x8x2 in high. You have 8x8x1 in high. Surface are of both is exactly the same-64 in-but capacity/volume is very different. Volume of 8x8x1 is 64 sq in, 8x8x2 is 128 sq in!

Smaug
February 10, 2020

Not really very relevant. If you're making soup or jello you can size your container by volume (to some extent) but in a baking recipe changing the depth significantly will have a huge effect both on the baking characteristics and the finished quality of the dish- it's generally to be avoided when adapting recipes.

mudd
February 10, 2020

That’s just what I’m trying to point out. Volume of pan can make a huge difference in baking!

Smaug
February 10, 2020

Then I'm not sure of the point of your post. If you're adapting a recipe, the depth of your pan should be similar to that of the original recipe, there's no real point in factoring in volume. It can be deeper, to some extent, but a too deep pan can slow down heat absorption from the top which may or may not be acceptable, and can also make it difficult to remove some things without damage; best to stay away from it. If you want to halve a recipe for a 1" deep pan you need a 1" deep pan, or close to it, with about half the surface area.

mudd
February 11, 2020

I’m trying to respond to some of the previous commenters/questioners below is all.

Katherine F.
January 26, 2020

I'm very new to baking, so this may be a no-brainer question, but i did the math and the difference between a 9 and 9.5 in tart pan is 1.1. Do i really need to increase the ingredients by .1%? I know you have to be pretty darn exact with baking..

Smaug
January 26, 2020

Actually, the difference is 11.4%- you can usually get away with ignoring it, but your filling may come out a bit thin. The need for exactitude in baking is greatly overstated- there are some things, such as fat to flour or liquid to flour ratios- where small changes can make a big difference (not necessarily a bad thing), but a lot of it is pretty wide open to variation.

Don B.
January 26, 2020

The ratio of the area of the two pans is the square of (9.5/9), or 1.114. This means the difference is .114 (1.114-1) or 11.4%, so you need to increase your ingredients by about 11%, not 0.1%.

Linda
December 26, 2019

Would you post a chart like you showed for baking pans, for cheesecake pans?

Recipe calls for one size and maybe you don’t have the same size or you want to create your own cheesecake but not sure how much of each ingredient you’d need.

Recipe calls for one size and maybe you don’t have the same size or you want to create your own cheesecake but not sure how much of each ingredient you’d need.

Bala R.
December 19, 2019

Such an interesting post!!! Loved the Math u have explained.. U have made it easier now..I have one small doubt.. For a round pan, the radius is alone taken into account for the calculation.. What if the pan's height varies?!! Assuming my pan is taller, the amount of batter gets in will be more than a shorter pan right?!! So how do you incorporate the pan's height?!!!

Waiting for your response. Thanks in Advance 😊

Waiting for your response. Thanks in Advance 😊

Smaug
December 19, 2019

When adapting a recipe, particularly cakes and pies, the baking characteristics are largely dictated by the depth as that determines the time needed for heat to penetrate to the center as well as the weight (particularly for cakes) that the structure should support. Therefore, every effort should be made to maintain the depth of the original recipe. Thus, for 1/2 the recipe you need 1/2 the surface area. Of course this seldom works out exactly with the pans you have but if it's not close the recipe will need considerable adaptation and may fail. Cooking a shallow cake in a deep pan will interfere somewhat with heat circulation to the top and is to be avoided if possible, but it's seldom disastrous and is often the only real alternative.

Rosalind P.
January 2, 2020

yeah -- it's very frustrating. I have more pans that any sane home baker should have, especially for a New York-sized kitchen, yet I'm always running across recipes for a size I don't have. The most frustrating is for the different depths: 2 inch or even three inch.

Smaug
February 10, 2020

Well, there's a certain amount of simple arithmetic involved in multiplying or dividing recipes, and if you're developing recipes you will be working with some basic ratios, such as fat to flour or liquid to powdered ingredients. Things with a lot of chemistry behind them, such as ice cream, will have more such ratios, but if you've mastered long division youshould have no problem with the arithmetic. Of course it's all "word problems"- you have to understand the processes to know what calculations to make.

Diana S.
September 26, 2019

I have found that, if you are starting your cake with a boxed mix, a full-sized sheet cake pan of approximately 18x26 will easily handle four boxed mixes.....just don’t add a lot of extras. I do this for poke cakes, Texas sheet cakes, blueberry coffee cake. Works great!

AnneB
September 15, 2019

This "simple" math made my head hurt. I didn't make it half way before I started feeling so stupid that I gave up. Too hard. :-(

Sharon I.
September 10, 2019

Thanks, Don! I know I can figure this out -- you and Alice give me all the confidence I need!

Janet M.
August 4, 2019

Problems like these conversions make me so happy I learned basic arithmetic in grade school--these are exactly like word problems I struggled through--and mastered--in 6th grade back in the mid-1950s. My problem before this article was that I was mostly thinking in terms of volume instead of surface area.

Smaug
June 27, 2019

A lot of times, you don't actually need to calculate areas, if you're comparing pans of the same shape. For instance, if you want to compare the area of a 9" round pan and an 8" round pan, it's a simple proportion of 9squared/8squared, or 81/64- 1 1/4 is close enough for baking. Since to calculate the area you're multiplying the diameter by pi/4 in both the numerator and denominator, they cancel each other out.

GBChelle
May 25, 2019

Hi! I found Ina Garten’s recipe for brownies that makes a sheetpan (12x18). But I love my brownies thick. Do you think it would work to make them in a 9x13 pan and just bake them longer? Or will that just be too much batter and the weight of all of that better would cause them to sink in the middle and not cook properly?

Sara
May 3, 2019

Hello,

This post is extremely helpful. Especially the chart. However, I’m having some uncertainty with scaling down, which seems to be what I need to do based on the volumes. I’m trying to determine how to scale the recipe/ingredients of three 8” rounds to one 9x13. Please help!

Thank you!

Sara

This post is extremely helpful. Especially the chart. However, I’m having some uncertainty with scaling down, which seems to be what I need to do based on the volumes. I’m trying to determine how to scale the recipe/ingredients of three 8” rounds to one 9x13. Please help!

Thank you!

Sara

Don B.
May 4, 2019

simple question, but it can be a little tricky. your original recipe for three 8" rounds has a surface area of about 151 square inches, whereas your 9"x13" pan has a surface area of 117 square inches. therefore, to fill your rectangular pan to the same depth as the three round pans, you'll need about 22% less batter (that's (151-117)/151 = .22 ). so, for example, if your recipe calls for 5 cups of flour, you'll actually need about 3.9 cups of flour.

Sara
May 4, 2019

I actually just thought of a clever solution! Make the recipe as is, weigh the finished batter, and remove about 1/4 (or as close to 22% I can get) of it, and use that for a few cupcakes. You’re reply was very helpful. Now I truly understand how to scale a recipe down with your example and calculations. Thank you again!

Lorie P.
April 30, 2019

So I did the conversion also using another method and using this method and another method my answer comes to roughly 1.8, my question is, is this the same factor you use if using multiple Cake layers? Recipe I’m using calls for 6, 6 inch rounds however I’m using 6, 8 inch rounds?

Don B.
April 30, 2019

Yup. going from a 6" round to an 8" round of the same depth means you need to multiply your recipe by 1.8, which is (8/6)^2 .

Lolly
April 17, 2019

Hi

I just found the most perfect cake recipe which may sound strange to most people but I am allergic to eggs, milk and have celiacs disease so cannot have wheat either. I haven’t had cake for a lot of years now well not without being ill :-/ The recipe I found is the first one to not have odd stuff in like a lot have chickpea flour which does not appeal to me and other various odd things.... whole other story... Anyhoo the recipe calls for a 9 inch round cake tin and says cook for 30-35 mins. I only have 8 inch cake tins which I do love and I have had a go at using which it looked absolutely perfect consistency when I was putting into the tins before it went into the oven.... I checked at 35 mins (not thinking of the relevance of the size) and it looked pretty good but wasn’t done (so gave another 5 and checked then another 5) looked really good and squewer came out clean... obviously out of practice at making cakes and forgot the whole opening the door who ha so collapse situation.. tastes good though! Do you think the time was right in total so next time if I did for 45 without opening the oven it would be ok or any theories on maths with the time for the smaller tin. Please let me know. May just have to suck it up and go buy 2x 9inch ones! Many thanks x

I just found the most perfect cake recipe which may sound strange to most people but I am allergic to eggs, milk and have celiacs disease so cannot have wheat either. I haven’t had cake for a lot of years now well not without being ill :-/ The recipe I found is the first one to not have odd stuff in like a lot have chickpea flour which does not appeal to me and other various odd things.... whole other story... Anyhoo the recipe calls for a 9 inch round cake tin and says cook for 30-35 mins. I only have 8 inch cake tins which I do love and I have had a go at using which it looked absolutely perfect consistency when I was putting into the tins before it went into the oven.... I checked at 35 mins (not thinking of the relevance of the size) and it looked pretty good but wasn’t done (so gave another 5 and checked then another 5) looked really good and squewer came out clean... obviously out of practice at making cakes and forgot the whole opening the door who ha so collapse situation.. tastes good though! Do you think the time was right in total so next time if I did for 45 without opening the oven it would be ok or any theories on maths with the time for the smaller tin. Please let me know. May just have to suck it up and go buy 2x 9inch ones! Many thanks x

Martha
April 1, 2019

Our household is down to two and I plan to start baking deserts in a six-inch round cake pan. I have a good sense from this article about how to cut down the ingredients. Is there a general rule of thumb about how to translate cooking times (many recipes call for an 8 or 9 inch round cake pan, same depth). Apologies if I have missed that herein!

Sabrennah
March 24, 2019

What if you wanted to do the opposite? Such as scaling down a recipe. I want to take my cake recipe, that calls for a 9 inch round and make 6 inch rounds with it...not sure how to cut the recipe in halve correctly? Thanks for any help!

Don B.
March 25, 2019

the math works the same scaling down as scaling up. One 6" round will use about 44% of the recipe of one 9" round. (44% is close enough to half as should make no difference.) So your recipe for a 9" round should make enough cake for two 6" rounds. (Or you could just halve the ingredients and make one 6" round.)

Jeff
February 1, 2019

How do I calculate from 8 round to cupcakes? Would the area math work for cupcakes and if so, is their a standard size for a cupcake?

Xan
January 28, 2019

I'm baking brownies and the recipe calls for an 8x8 pan but i want to bake it in a 9x9 pan. I followed your computation and end up to 1.50. How can i double my recipe?

Salma
January 20, 2019

I want to halve a recipe that calls for a 9 inch springform pan. What size pan should I use instead?

Don B.
January 21, 2019

To fill the pan to the same depth, you'll want to use a pan that's 6.3” in diameter (or as close as you can get) - that's 9” divided by the square root of 2 (0.707).

Annie
January 19, 2019

I’m making cornbread and have a 9” square pan, not the 8” a square pan called for in the recipe. How do I adjust the cooking time?

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