Pan size converter compares geometric capacity. Enter the dimensions of the space inside each pan, the number of pans, and the fill-depth assumption. Product labels may describe external dimensions, so check what you are measuring.
Choose the actual shape
For a round pan, enter the internal diameter. For a square pan, enter the internal side length. For a rectangular pan, enter internal length and width. Use consistent units or make an explicit unit conversion.
The simple models assume straight sides. Tapered, fluted, domed, or irregular pans may not match them closely. Keep that limitation with the result rather than treating an outline measurement as an exact capacity.
Check depth and pan count
Choose Full geometric capacity to compare each pan using its entered internal depth. Choose The same filling depth to compare both at one specified fill depth, entered in the original pan’s unit. Choose A specified fill percentage to use the same percentage of each pan’s modeled capacity.
Include every pan in the batch. Two identical pans provide twice the modeled capacity of one at the same depth. Dimensions must be positive, the common fill depth must fit inside both pans, and the pan count must be a whole number from 1 to 100.
Inspect a simple comparison
A round 8-inch pan compared with a round 9-inch pan at the same fill depth has a ratio of 8² ÷ 9² = 64/81, or approximately 79.01%. A 180 g ingredient scaled by that geometric ratio becomes approximately 142.22 g.
This example compares diameters, so the common circle constants cancel. It does not establish whether that particular recipe will rise, set, or cook successfully in the new pan.
Correct missing or invalid dimensions
A zero diameter, an unsupported dimension, or a negative count cannot describe a usable comparison. Read the error message, correct the relevant input, and inspect the refreshed ratio before applying it to a recipe.
If you cannot establish internal dimensions, keep the result as an estimate or use a more appropriate known capacity. Do not fill unknown fields with convenient numbers solely to enable the calculation.
Use the ratio with judgment
The result can help you choose an ingredient scaling factor. Cooking time, temperature, clearance for rising, and the recipe’s behavior remain separate decisions. The converter does not supply a safe-fill certification or an automatic time adjustment.