Pan Size Converter

Last updated: Jun 9, 2026

Available in: English, Español, Deutsch, Français, Ελληνικά, Nederlands, Italiano

Convert recipes between different pan sizes and shapes. Select your source and target pans, adjust layers, and get the exact scale factor with baking time recommendations.

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About This Tool

This pan size converter helps you adapt baking recipes when you do not have the pan called for in the original recipe. It covers 7 common pan shapes: round, square, rectangular (including sheet pans), bundt, springform, loaf, and tube (angel food). For a cake or bar, it compares the baking area of the source and target pans to set the scale factor, following King Arthur Baking's method of matching the pan's bottom surface so the batter bakes at the same depth. For recipes that use several pans (such as a two-layer or three-layer cake), the multi-layer feature combines them before the comparison. When the batter depth changes significantly between pans, the tool recommends baking time and temperature adjustments: deeper batter needs a lower temperature and longer time to bake evenly, while shallower batter bakes faster at the original temperature. Pan volumes come from standard geometry (pi × r² × depth for round pans, length × width × depth for rectangular pans), which King Arthur confirms: a 9-inch round and an 8-inch square each hold about 8.8 cups. Bundt and tube pans use their listed cup capacity. Sources are King Arthur Baking, with Joy of Baking and Sally's Baking Addiction for common pan sizes. All processing runs entirely in your browser with no data sent to any server.

Sources: Joy of Baking · King Arthur Baking · Sally's Baking Addiction

How to Use

Select the shape and size of your source pan (the pan in the original recipe). Set the number of layers if the recipe uses multiple pans.
Select the shape and size of your target pan (the pan you want to use instead). You can choose a preset or enter custom dimensions.
Review the scale factor, volume comparison, and baking adjustments. If there is an overflow warning, consider using a larger pan or splitting the batter.

Methodology

Pan volume uses standard geometric formulas: round and springform pans, V = π × (d/2)² × depth; square pans, V = side² × depth; rectangular and loaf pans, V = length × width × depth. Bundt and tube pans have no formula, so they use their listed cup capacity. Baking area is the pan's bottom surface: π × (d/2)² for round shapes, side² for square, length × width for rectangular. For cakes and bars the recipe scale factor is the target baking area divided by the source baking area (multiplied by the layer counts). King Arthur uses area so the batter keeps the same depth in the new pan; bundt and tube pans, which have no area, scale by the cups ratio instead. Time and temperature adjustments are a guideline, not a formula. When the batter sits more than about 10% deeper, the tool estimates a longer baking time (shown as a percentage) and suggests lowering the temperature by about 25°F (14°C); more than about 10% shallower, it estimates a shorter time. The overflow warning triggers when the target pan holds less than about two-thirds of the source's total capacity.

Sources: Joy of Baking · King Arthur Baking

Understanding Your Results

Your pan conversion results show how to adapt a recipe designed for one pan size to a different pan. Two factors matter most: baking area and batter depth. Baking Area: For cakes and bars the converter compares the baking area (bottom surface) of the original and target pans, then provides a scaling factor for your recipe. A 9-inch round pan has about 63 square inches of area, while an 8-inch round has about 50 square inches — the 9-inch holds about 27% more. Ignoring this difference means your cake will be either too thin (too large a pan) or overflow (too small a pan). Batter Depth: For most cakes, batter should fill the pan ½ to ⅔ full. Overfilling causes batter to rise over the sides; underfilling produces a flat, dense result. When converting to a larger pan, the thinner batter layer bakes faster and may need 5–10 minutes less time. When converting to a smaller pan, the thicker layer needs more time and a slightly lower temperature to cook through without burning the edges. Shape Conversions: Converting between shapes (round to square, round to rectangular) is based on baking area. A 9-inch round pan has approximately the same area as an 8-inch square pan. A 9×13-inch pan has close to the area of two 9-inch round pans — so a two-layer cake recipe converts directly to a single 9×13 sheet cake. Serving Size: Pan size directly affects serving count. Industry-standard cake servings are 1×2-inch slices for single-layer or 1×1×2-inch pieces for layer cake. A 9-inch round single layer yields approximately 12 servings, while a 9×13 sheet yields approximately 24 servings.

Practical Examples

Example 1: Converting a 9-inch Round to an 8-inch Square Original recipe: designed for one 9-inch round pan 9-inch round area: π × 4.5² = 63.6 sq inches 8-inch square area: 8 × 8 = 64 sq inches Scaling factor: 64 / 63.6 = ~1.01 (virtually identical) Result: Use the same recipe amounts. No adjustment needed. This is the most common pan swap in baking because the volumes are nearly identical. Baking time: Same as original Example 2: Converting Two 9-inch Rounds to One 9×13 Sheet Original recipe: designed for two 9-inch round layers Two 9-inch rounds total area: 2 × 63.6 = 127.2 sq inches 9×13 rectangular area: 9 × 13 = 117 sq inches Scaling factor: 117 / 127.2 = ~0.92 (sheet is slightly smaller) Result: The batter will be slightly deeper in the sheet pan. Use the full recipe amount; the 8% difference is negligible. Baking time: Add 10–15 minutes since the batter is deeper. Check with a toothpick at the original time.

Pan Conversion Tips

• When converting to a different pan size, adjust baking time but keep oven temperature the same (unless going much larger or smaller). Thinner batter layers bake 5–10 minutes faster; thicker layers need 5–15 minutes longer. Check doneness with a toothpick starting 5 minutes before the adjusted time. • Use parchment paper or grease-and-flour for any converted pan, especially when using a shape different from the original recipe. Batters behave differently in corners (square pans) versus curved edges (round pans), and proper pan prep prevents sticking. • For two-layer round cake recipes converted to a single sheet pan, pour all the batter into one pan and increase baking time by 10–15 minutes. The result is a single thick layer that can be cut in half horizontally for layering, or served as a sheet cake. • Glass and dark-colored pans absorb more heat than light aluminum pans. When using glass or dark pans, reduce oven temperature by 25°F (14°C) to prevent over-browning the edges before the center is done. This applies to all pan sizes. • Springform pans are taller than standard cake pans (about 2½ to 3 inches) and have a base seam that can leak. They are ideal for cheesecakes and delicate cakes you want to release without inverting. When baking a loose or liquid batter, wrap the outside of the springform in foil (or set it in a water bath) so the batter cannot seep out at the seam.

Sources: King Arthur Baking · Sally's Baking Addiction

Pan Size Quick Reference

Sources

All calculations are performed locally in your browser. No data is sent to any server.

Bundt® is a registered trademark of Nordic Ware. — Smithsonian National Museum of American History

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Frequently Asked Questions

How do I convert between round and square pans?

Select the source pan shape and size (e.g., 9-inch round), then select the target pan shape and size (e.g., 8-inch square). This converter compares the baking area (the bottom surface) of each pan and shows the scale factor for your recipe. A 9-inch round pan has about 63.6 square inches of area, while an 8-inch square has 64, so they are nearly equivalent and can be swapped without changing the recipe. The tool also adjusts baking time when the batter depth changes significantly.

How does multi-layer conversion work?

When a recipe uses more than one pan (e.g., two 8-inch round layers), set the source layers to 2. The converter combines the layers — two 8-inch rounds hold about 13.9 cups together — and compares that with the target pan. This tells you whether the batter fits: a single 9×13-inch pan holds about 16.2 cups, so the two layers' worth of batter fits with room to spare and bakes as one thicker cake, which needs more baking time. The recipe scale factor is based on baking area, so it reflects how the batter thickness changes between the pans.

Why does the tool adjust baking time and temperature?

When you change pan sizes, the batter depth changes. A deeper batter layer takes longer to bake through, while a shallower layer bakes faster. As a general guideline, if the batter is deeper in the new pan, increase baking time by 5-10 minutes and consider reducing temperature by about 25°F (14°C) to prevent the outside from over-browning before the center is done. If the batter is shallower, reduce baking time and keep the original temperature.

What does the overflow warning mean?

The overflow warning appears when the target pan is too small to hold the batter — specifically, when its capacity is less than about two-thirds of the source pan's total capacity. Because a cake or bar recipe fills its pan only about half to two-thirds full, that much batter would rise over the rim during baking. Choose a larger target pan, split the batter into multiple pans, or reduce the recipe to fit.

Can I enter custom pan dimensions?

Yes, select any shape and then enter custom dimensions instead of using a preset. For round and springform pans, enter the diameter and depth. For square pans, enter the side length and depth. For rectangular and loaf pans, enter the length, width, and depth. For bundt and tube pans, enter the cup capacity (fill the pan with water to the rim and measure). Measurements are in inches, or centimeters in metric mode; capacity is in cups, or milliliters.

How do I know if my batter will overflow when using a smaller pan?

This tool automatically calculates the volume ratio between your original and target pans and warns you when the target pan's capacity is too small. As a general rule from King Arthur Baking, fill cake pans only about half to two-thirds full to allow room for rising. If the converter shows an overflow warning, you can either choose a larger target pan, split the batter across multiple pans, or reduce the recipe proportionally to fit the smaller pan.

What are the most common pan size substitutions?

The most common swaps: a 9-inch round pan and an 8-inch square pan have almost the same baking area (about 64 square inches, roughly 8.8 cups), so they are interchangeable. A 9×13-inch pan can be replaced by two 9-inch round pans (the two rounds hold about 10% more, giving a little rise room). An 11×7-inch pan is close in area to a 9-inch square pan (77 versus 81 square inches). And a 10-cup Bundt pan holds about the same batter as one 9×13 pan or a two-layer round cake.

How do I convert a recipe from a round pan to a sheet pan?

Set the source to Round and the target to Rectangular, then select the sheet pan size (such as 9×13 or a half-sheet). If your round-pan recipe uses multiple layers, set the source layers accordingly — for example, two 9-inch round layers. The converter will compute the total source volume and compare it to the sheet pan volume. A typical two-layer 9-inch round cake (about 18 cups total) fits well in a single 9×13 pan (16 cups), with the batter slightly deeper. Increase baking time by 10-15 minutes for the thicker layer.

What is the difference between springform and regular round pans?

Springform pans are typically deeper than standard round pans (about 2½ to 3 inches versus 2 inches) and have a removable base held by a side clasp, so you can release a cake without inverting it. A 9-inch springform that is 3 inches deep holds about 13 cups, compared with about 8.8 cups for a standard 9-inch round that is 2 inches deep. Springforms are the usual choice for cheesecakes, delicate tortes, and any cake you want to unmould intact. Because the base seam is not fully sealed, wrap the outside in foil (or use a water bath) when baking a very loose batter such as cheesecake. When converting between the two, the tool accounts for both the capacity difference and the change in batter depth.

Can I use a loaf pan instead of a round pan?

A 9×5-inch loaf pan holds about 9 cups, close to a 9-inch round pan's 8.8 cups, but the two bake very differently: the loaf's narrow, deep shape carries heat to the center slowly. Loaf pans are best for dense batters — pound cake, banana bread, and other quick breads — not for light sponge cakes, which may not rise evenly in the narrow shape. If you do move a round recipe into a loaf pan, the batter will be deeper: reduce the oven temperature by about 25°F (14°C), add 10-15 minutes, and check the center with a toothpick. King Arthur notes that a slightly longer loaf pan can hold nearly 20% more, so match loaf sizes carefully.

How do I split a recipe between multiple smaller pans?

Use the multi-layer feature to find a match that holds the batter. Set the source pan to the original recipe size with 1 layer, then set the target to a smaller pan with more layers. For example, if your recipe calls for one 9×13 pan (about 16 cups), set the target to a 9-inch round with 2 layers (about 17.6 cups total) — King Arthur's recommended swap for a 9×13 cake. The converter shows the scale factor and whether to adjust ingredient amounts. Divide the batter equally between the pans; a kitchen scale helps. Smaller pans with thinner batter layers typically bake 5-10 minutes faster than the original, so start checking early.

Do I need to adjust baking time when changing pan sizes?

Usually yes. The key factor is batter depth, not pan volume alone. When the batter sits deeper in the new pan, the center takes longer to bake through — add 5-15 minutes and reduce temperature by about 25°F (14°C) to prevent the edges from burning before the center sets. When the batter is shallower, reduce baking time by 5-10 minutes. This converter automatically estimates these adjustments based on the depth ratio between your pans. Always check doneness with a toothpick inserted into the center starting 5 minutes before the adjusted time.