## Recipe Quantity Conversion?

By AusSas Updated 8 Oct 2013 , 11:05pm by sewsugarqueen

AusSas Posted 6 Oct 2013 , 5:28am
post #1 of 9

Hi, does anyone have a link to a calculator where I can plug in an original recipe and change the size pan to get quantities to make a different size cake?  I've seen one in the past where you can enter in the original recipe and say it was for a 9" cake, and you can change it to a 7" cake and it will alter the amount of ingredients appropriately.

Thanks. :-)

8 replies
sarahgale314 Posted 7 Oct 2013 , 2:15am
post #2 of 9

AI made my own... I have a degree in math and taught high school math for 4 years before I quit to have kids and then started baking. Anyway, I worked out for myself a while ago multipliers to multiply recipes by, using ratios of the pan volumes. Here are the multipliers for all pan sizes, with a 2-layer 9-inch cake baked in 2-inch pans (what the majority of recipes are written for) as multiplier "1."

So, if you have a recipe for a cake baked in 2 nine inch pans that are two inches high, multiply the recipe by the numbers shown below to convert it to 2 two inch high land in the specified diameter.

To bake a cake in 2 pans this size: Multiply all ingredients by: 4 inch. 0.2 5 inch. 0.3 6 inch. 0.44 7 inch 0.6 8 inch. 0.8 9 inch. 1 10 inch. 1.2 11 inch. 1.5 12 inch. 1.8 13 inch. 2 14 inch. 2.5

The mathematical explanation is: you're working with volumes of cylinders, which is: number of pans*pi*radius^2*height. Then, to figure out the amount of batter you need, you take the volume of the pan you want to use and divide it by the volume of the pan used in the recipe you have. When you divide things that are all multiplied together in math, any number on the top of the fraction can be cancelled out with the same number on the bottom of the fraction, so if the pans are both 2 inches high, the 2s cancel out. Also, the pi on top and bottom both cancel out, so you are left with the squares of the radii of the pans. The radius is half the length of the diameter, so a 9-inch pan has a radius of 4.5 inches.

If you want to bake a recipe in more than two pans, then you will need to do number of pans*radius^2 divided by number of pans used in the recipe*radius^2 of pan in recipe.

soldiernurse Posted 7 Oct 2013 , 2:49am
post #3 of 9

AInteresting..very good to know..

KathleenC Posted 7 Oct 2013 , 6:21am
post #4 of 9

You lost me at "math", but thank you for the multipliers.  Very handy info to have.

brendajarmusz Posted 7 Oct 2013 , 6:30am
post #5 of 9

AI'm lost also lol. Math was never my strong suite

kkmcmahan Posted 7 Oct 2013 , 11:28am
post #6 of 9

Thank you Sara, this is great! Can't tell you how many times I could have used this in the past...it is going to be pinned to my wall!

sarahgale314 Posted 8 Oct 2013 , 10:38pm
post #7 of 9

sewsugarqueen Posted 8 Oct 2013 , 11:02pm
post #8 of 9

Actually there is something called a baker's rule where the flour amount =100% and then work out the proportions of all else based on flour's weight... means get out the calculator.  As my momma use to say you can't always double and triple everything sometimes it just don't work.  go on line and look up baker's rule to explain more.  That's one way to change a single cake recipe into larger numbers.  Just a suggestion.

sewsugarqueen Posted 8 Oct 2013 , 11:05pm
post #9 of 9

sorry just realized your question was based on pan size not how much more to make for larger pans.... Having one of those moments..