How do I convert a cake recipe to a different pan size?

Compare the base area of the two pans and multiply the recipe by the ratio between them. A round pan area is pi times the radius squared, a square is the side squared, and a rectangle is length times width. Scaling by area keeps the batter the same depth, which is what keeps the bake time and texture close to the original. This tool does the geometry for you.

Why scale by area rather than diameter?

Because area grows with the square of the size, not linearly. An eight-inch and a nine-inch round pan sound similar, but the nine-inch holds about a quarter more batter. Scaling by diameter would leave you well short. Using the base area captures the real difference in how much mixture each tin holds.

Do I need to change the oven temperature or bake time?

Keep the temperature the same, because batter depth rather than temperature drives how a cake bakes. If the new pan is much larger the batter is spread thinner and bakes a little faster, and if it is smaller and deeper it bakes a little slower. Start checking a few minutes earlier or later than the original recipe and use a skewer to confirm.

Can I convert between round, square and rectangular pans?

Yes. The converter works across all three shapes because it reduces every pan to its base area first. That means you can move a recipe from a round tin to a square one, or from a single rectangle to a round layer cake, and still get a scale factor that keeps the batter depth sensible.

What is the Cake Pan Size Converter?

Baking in a different tin than the recipe calls for? Convert between round, square and rectangular pans by base area to get the exact factor to multiply your recipe by, keeping the batter depth and bake time right. It runs free in your browser on Gera Tools, with nothing uploaded.

Cake Pan Size Converter

Name: Cake Pan Size Converter
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Bake in the tin you actually own

Recipes are written for a specific pan, but the tin in your cupboard is rarely the exact one. Guess the scaling and you end up with batter overflowing the sides or a thin, dry layer that bakes in half the time. The reliable fix is to scale by base area, and this converter works it out for round, square and rectangular pans in either inches or centimetres.

Why area is the honest measure

Pan capacity grows with area, which rises with the square of the size. That is why a nine-inch round holds noticeably more than an eight-inch one despite the small difference in diameter. The tool computes the base area of both pans — using pi r squared for rounds and length times width for the rest — and gives you the ratio between them as a single scale factor. Multiply every ingredient by it and the batter fills the new tin to the same depth as the original.

Keep the temperature, tweak the time

Because scaling by area holds the batter depth roughly constant, you keep the oven temperature exactly as written. The only adjustment is timing: a wider, shallower tin bakes a little faster and a smaller, deeper one a little slower. Start checking for doneness a few minutes either side of the original time and trust a skewer rather than the clock, and the cake will come out just as it should.