Adjust ingredient amounts when switching to a different pan size, based on surface area.
Switching a recipe to a different pan size changes how thick the batter sits, which affects baking time and ingredient amounts. This calculator scales ingredient quantities based on the surface area of your original and new pan.
Scaling Factor = New Pan Area ÷ Original Pan Area. New Ingredient Amount = Original Amount × Scaling Factor. Round pan area uses π × r²; rectangular pan area uses length × width.
Moving a recipe from an 8-inch round pan (50 sq in) to a 9x13-inch rectangle (117 sq in) needs about 2.3× the ingredients (117 ÷ 50).
Because batter depth changes with pan size, also adjust your baking time — a thinner layer in a larger pan usually bakes faster, so start checking a few minutes early.
It compares the volume (or area, for shallow pans) of your original pan size to a new pan size, then suggests how to scale the recipe or adjust bake time accordingly.
A round and a square pan with the same area will bake differently because of edge exposure and batter depth, so this calculator accounts for area and shape together, not volume alone.
Yes — a deeper pan generally needs a longer bake at a slightly lower temperature, while a shallower, wider pan bakes faster at the same or slightly higher temperature.