Pan Size Converter 🍳

Free pan size converter for round, square, rectangular, and bundt pans. Calculate the exact recipe scale factor when substituting one pan size for another.

The Pan Size Converter scales any cake or quick-bread recipe when you swap one baking pan for another. It compares the volume of your source pan to the target pan and returns a single scale factor you can multiply across every ingredient in the recipe — flour, sugar, eggs, leavening, the lot. Most home bakers run into this problem because professional recipes are written for an 8-inch round but home bakers often only own a 9-inch round, an 8×8 square, or a 9×13 rectangle. Substituting blindly leads to overflowing batter, sunken centers, or dry edges. The converter assumes a standard 2-inch (5 cm) batter depth, which is the industry-standard depth used in most modern cake recipe references, and supports round, square, rectangular, and bundt pans. Use it before you start mixing so you can also adjust baking time and oven temperature for the new pan.

How to Use the Pan Size Converter

  1. Select Source Pan — Choose the pan type (round, square, rectangular, or bundt) and size used in the original recipe.
  2. Select Target Pan — Choose the pan type and size you want to use.
  3. Apply Scale Factor — Multiply all recipe ingredients by the calculated scale factor. A factor greater than 1 means increase ingredients; less than 1 means decrease.
  4. Adjust Baking Time — A larger pan with thinner batter bakes faster — reduce baking time by 5–10 minutes and check 10 minutes early. A smaller pan with deeper batter needs longer; lower the oven by 25 °F (15 °C) and add 10–15 minutes.
  5. Fill Pan Correctly — Never fill a pan more than two-thirds full. If the scale factor pushes batter beyond that line, divide between two pans rather than risk overflow.

Formula Reference

Scale factor = target pan volume ÷ source pan volume. Round pan volume = π × radius² × depth. Square pan volume = side² × depth. Rectangular pan volume = length × width × depth. Bundt pan volume is rated by cup capacity from the manufacturer (10-cup bundt ≈ 144 cubic inches at standard depth). The converter uses a fixed batter depth of 2 inches because most cake and quick-bread recipes are formulated for this depth. Multiply the scale factor across every ingredient by weight: new ingredient weight = original weight × scale factor.

Source: Rose Levy Beranbaum, The Cake Bible (Scribner, 2016) — Pan Volume Reference; Shirley Corriher, BakeWise (Scribner, 2008) — Pan Geometry chapter.

FAQ

Can I make an 8-inch pan recipe in a 9-inch pan?

Yes! A 9-inch pan is about 27% larger than an 8-inch pan. Multiply all ingredients by approximately 1.27. Since the batter spreads thinner, reduce baking time by 5–10 minutes.

Can I substitute a bundt pan with a regular round pan?

Yes. A 10-cup bundt pan holds about 10 cups, which can be replaced by two 9-inch round pans or one 9×13-inch rectangular pan.

Why use volume instead of diameter to scale a recipe?

Volume captures the total amount of batter the pan holds. Two pans with similar diameters can have very different volumes if they are different shapes — for example, an 8-inch round (≈101 cubic inches) holds less than an 8-inch square (≈128 cubic inches). Scaling by volume keeps the cake's height and crumb consistent.

Do I need to change oven temperature when swapping pan sizes?

For small swaps (8 to 9 inch round), keep the temperature the same and only adjust time. For large swaps to a deeper or smaller pan, lower the oven by 25 °F (15 °C) so the center finishes before the edges burn. Dark or non-stick pans should also bake 25 °F lower.

Does the converter work for cheesecakes and bar cookies?

Yes for bar cookies and brownies, which behave like quick breads. For cheesecakes, scale carefully — the egg ratio matters. Use the volume scale factor for the filling, but keep crust thickness similar. A 9-inch springform cheesecake recipe scaled to a 10-inch pan needs about 1.23× ingredients.

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