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Generated on: July 20, 2026 at 09:33 PM

Cake Pan Conversion Calculator

Inputs

Original pan shapeRound
Original pan size23 cm
Original pan width33 cm
New pan shapeSquare
New pan size20 cm
New pan width30 cm

Surface-area scaling keeps the batter at a similar depth but cannot account for differences in pan material, colour, or how a recipe behaves when scaled. Dark or thin pans bake faster, and very large changes in batch size can affect rise and texture. Treat the scale factor as a starting point and check doneness with a tester.

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Food & Cooking

Cake Pan Conversion Calculator

Convert a cake recipe between pan sizes and shapes. Compare two pans by surface area and get the exact factor to multiply your batter by.

Inputs

≥ 0 cm
≥ 0 cm

Results

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Details

Your new pan has a different surface area than the original, so multiply every batter ingredient by ... to keep the cake at a similar depth. Keep the batter depth comparable and adjust the baking time and temperature as needed.

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Cake Pan Conversion

Swapping one cake pan for another is mostly a question of batter depth. A recipe is written to fill a particular pan to a particular height, and that height is what determines how the cake rises and how long it bakes. The reliable way to keep the depth the same in a different pan is to match the surface area of the pan bottoms and scale the batter by the ratio between them.

The amount of batter you need is proportional to the area of the pan, not its width or its name. A pan called "20 cm" can be round or square and hold quite different volumes, so comparing areas directly avoids guesswork. Multiply every ingredient in the batter by the scale factor this calculator returns, then pour and bake.

Comparing pan areas

The area of each pan depends on its shape. For a round pan of diameter aa, a square pan of side aa, and a rectangular pan of length aa and width bb:

Around=π(a2)2Asquare=a2Arectangle=a⋅b\begin{aligned} A_{\text{round}} &= \pi \left(\frac{a}{2}\right)^2 \\ A_{\text{square}} &= a^2 \\ A_{\text{rectangle}} &= a \cdot b \end{aligned}

The scale factor is simply the ratio of the new pan area to the original pan area:

scale=AnewAorig\text{scale} = \frac{A_{\text{new}}}{A_{\text{orig}}}

Worked example — a recipe for a 23 cm round pan, baked in a 20 cm square pan:

Aorig=π(232)2≈415 cm2Anew=202=400 cm2scale=400415≈0.96\begin{aligned} A_{\text{orig}} &= \pi \left(\frac{23}{2}\right)^2 \approx 415\ \text{cm}^2 \\ A_{\text{new}} &= 20^2 = 400\ \text{cm}^2 \\ \text{scale} &= \frac{400}{415} \approx 0.96 \end{aligned}

The pans are within a few percent of each other, so you barely need to change the recipe — multiply each ingredient by about 0.96.

Worked example — a recipe for a 9 inch round pan, baked in an 8 inch square pan:

Aorig=π(92)2≈64 in2Anew=82=64 in2scale=6464≈1.0\begin{aligned} A_{\text{orig}} &= \pi \left(\frac{9}{2}\right)^2 \approx 64\ \text{in}^2 \\ A_{\text{new}} &= 8^2 = 64\ \text{in}^2 \\ \text{scale} &= \frac{64}{64} \approx 1.0 \end{aligned}

These two pans have almost the same area, so the recipe transfers across with essentially no change.

Keep the depth, watch the time

Scaling by area keeps the batter at roughly the same depth, which is what makes the conversion work. If you instead pour a full batch into a much smaller pan, the batter rises too high, overflows, or bakes unevenly. If you spread it into a much larger pan, it bakes into a thin, dry layer.

Because depth stays similar, the baking time usually stays close to the original. The exceptions are worth knowing. A shallower, wider pan exposes more surface and bakes faster, so check it several minutes early. A deeper, narrower pan bakes more slowly, and lowering the oven temperature by about 15 °C (25 °F) gives the centre time to set before the edges overbake. Dark or thin metal pans also brown faster than light, heavy ones. Whatever the pan, a skewer inserted into the centre is the final word on doneness.

For planning how many people a finished cake will feed, see the Cake Servings Calculator. To scale a full recipe up or down by servings rather than by pan, use the Recipe Scaler.

Frequently Asked Questions (FAQ)

Can I bake a recipe in a different cake pan?

Yes, as long as you adjust the amount of batter so it sits at a similar depth. The trick is to match the surface area of the pan bottoms, because that is what controls how thick the batter will be. For example, a standard 23 cm round pan has an area of about 415 cm², while a 20 cm square pan has 400 cm² — almost identical, so you can swap them with no change. A 20 cm round pan (314 cm²) holds noticeably less, so you would scale the batter down to about 0.76 of the original. This calculator does that math for you and gives the exact multiplier.

Yes, as long as you adjust the amount of batter so it sits at a similar depth. The trick is to match the surface area of the pan bottoms, because that is what controls how thick the batter will be. For example, a standard 9 inch round pan has an area of about 64 in², while an 8 inch square pan has 64 in² — almost identical, so you can swap them with no change. An 8 inch round pan (50 in²) holds noticeably less, so you would scale the batter down to about 0.76 of the original. This calculator does that math for you and gives the exact multiplier.

How do I adjust the baking time for a different pan?

Baking time follows the batter depth, not the pan area. If the new pan keeps the batter at roughly the same depth, the time stays close to the original.

A shallower, wider pan bakes faster — start checking 5 to 10 minutes early. A deeper, narrower pan bakes more slowly and may need extra time, and lowering the oven temperature by about 15 °C (25 °F) helps the centre cook through before the edges overbake. Always test with a skewer or cake tester rather than relying on the clock alone.

Does a square pan hold more than a round pan of the same size?

Yes. A square pan holds more batter than a round pan whose diameter matches the square's side, because the round pan loses the four corners. A 20 cm square pan has an area of 400 cm², while a 20 cm round pan has only about 314 cm² — roughly 27 percent more in the square. That is why bakers often say a square pan is "one size up" from the round pan of the same nominal measurement.

Yes. A square pan holds more batter than a round pan whose diameter matches the square's side, because the round pan loses the four corners. An 8 inch square pan has an area of 64 in², while an 8 inch round pan has only about 50 in² — roughly 27 percent more in the square. That is why bakers often say a square pan is "one size up" from the round pan of the same nominal measurement.

Disclaimer

Surface-area scaling keeps the batter at a similar depth but cannot account for differences in pan material, colour, or how a recipe behaves when scaled. Dark or thin pans bake faster, and very large changes in batch size can affect rise and texture. Treat the scale factor as a starting point and check doneness with a tester.

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