Baking pan
size converter.
Compare base areas to estimate how ingredient quantities could change for a similar batter depth.
Compare your pans
Area-based estimateAssumes straight sides, comparable usable depth, and similar batter depth. Measure internal dimensions. Does not determine baking time or safe fill level.
How the estimate works
Round area = π × (diameter ÷ 2)². Rectangular area = width × length. Multiply by the number of pans on each side, then divide the new total area by the original total area.
For one 8-inch round pan to one 9-inch round pan, the factor is 81 ÷ 64 = 1.265625. The display rounds this to 1.27×. This is geometry, not a tested recipe adaptation.
Where area is not enough
Pan depth, taper, material, batter behavior, and the recipe's intended fill level also matter. This tool does not support tube pans, Bundt pans, irregular shapes, or pans with very different usable depths.
Do not multiply baking time by the factor. Use the recipe author's adaptation advice and doneness guidance. A deeper pan is not automatically permission to fill it with more batter.
Changing inches to centimeters converts the dimensions already entered. Both sets of pans always use the same unit.
Prototype calculation · Practical guidance pending editorial review
Measure your pan’s opening, depth, and capacity before choosing dimensions →