Cake Pan Size Converter

Compare two pans

Enter the inside size of the pan in your recipe and of the pan that you own. The converter compares the areas of the two pans. The area sets how deep the batter is, and the depth changes the baking time.

Equal-area pan table

Area uses the inside size, measured from inside edge to inside edge. Round pan area = π × r². Square and rectangle area = length × width. The factor is the area of the substitute pan ÷ the area of the pan in the first column. Multiply each ingredient by the factor to keep the same batter depth.

A 9 x 13 pan has 1.8391 times the area of one 9 inch round (117.000 ÷ 63.617). A 9 inch round has 1.2656 times the area of an 8 inch round (63.617 ÷ 50.265). Two 9 inch rounds have 127.235 sq in, which is not equal to one 9 x 13 pan.

Only the 9 inch round and the 8 x 8 square are less than 1% different. The other pairs differ by 3% to 13%. For those pairs, multiply each ingredient by the factor, or expect a different batter depth.

The pan conversion formula

Factor = area of your pan ÷ area of the recipe's pan. Multiply every ingredient by that number to keep the same batter depth. If you keep the recipe amount and change only the pan, the batter in the pan with the larger area is shallower and bakes faster. In the pan with the smaller area, the batter is deeper and takes longer to bake.

Joyofbaking says that the ideal substitute pan keeps the same batter depth, because it keeps the same pan area. Its example is an 8 x 8 inch square pan in place of a 9 inch round pan, with no change to the baking time or the oven temperature. This page calculates 64.000 sq in for the 8 x 8 pan and 63.617 sq in for the 9 inch round. Round pans: area = π × r². Square or rectangular: area = length × width.

Joyofbaking also gives a pan conversion formula with volumes: the volume of the pan you want to use ÷ the volume of the pan in the recipe. That ratio compares how much each pan holds to the brim. It is not the same as the area factor. The two pans can have different depths, and the cup values of Joyofbaking are approximate. For example, a 10 x 2 inch round holds 11 cups and a 9 x 2 inch round holds 8 cups. 11 ÷ 8 = 1.375, but the area factor is 1.2346.

Bake-time guidance from Joyofbaking

• Same area: the batter depth stays the same, so you do not have to make large changes to the baking time and the oven temperature.
• Shallower batter (bigger area): shorten the baking time and raise the oven temperature slightly.
• Deeper batter (smaller area): lengthen the baking time and lower the oven temperature slightly. This keeps the batter from over-browning.

How this page calculates

Pan sizes, cup volumes and the rule to keep the same pan area come from the Joyofbaking pan-size reference (joyofbaking.com/PanSizes.html), fetched 2026-10-29. The unit factors 1 inch = 2.54 cm and 1 sq in = 6.4516 sq cm come from NIST Special Publication 811, Appendix B.8, fetched 2026-10-29.

• Round pan area = π × (diameter ÷ 2)².
• Square pan area = side × side. Rectangle pan area = length × width.
• A size in cm is divided by 2.54 to get inches. Area in sq cm = area in sq in × 6.4516.
• Factor = area of your pan ÷ area of the recipe's pan.
• Batter depth in your pan with the recipe amount = recipe depth × (area of the recipe's pan ÷ area of your pan) = recipe depth ÷ factor.

The Joyofbaking example gives a rounded area for the 9 inch round pan. This page uses π × 4.5² = 63.617 sq in. All areas and factors on this page are calculated with the formulas above. The cup and metric volumes are the values of the Joyofbaking table.

Cake pan volume chart

Approximate capacity to the brim, as the Joyofbaking table gives it. The metric sizes and volumes are the rounded values of that table. Joyofbaking uses 1 inch = 2.54 cm and 1 cup = 237 ml. NIST gives 1 U.S. cup = 236.5882 mL.

Pan dimensions and capacities from the Joyofbaking baking pan sizes reference (iFood Media LLC).

Frequently Asked Questions