Pan Size Converter
Compare baking pans and adjust a recipe using equal-depth surface-area scaling.
Compare your pans
Choose the original pan and the replacement pan. Matching depth is assumed for the clearest estimate.
This converter uses pan surface area and assumes the pans are equally deep. Batter depth, pan material, oven behaviour and recipe structure can change baking time and doneness. Adjust baking time only as needed and check the centre independently.
Different depths are flagged as guidance only; this tool does not silently switch to volume-based scaling.
Pan size notes
Round area uses π × radius². Square and rectangular area use length × width. Metric and imperial dimensions are converted internally before comparison.
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How to use this tool
Select the shape of the source pan and the shape of the replacement pan, enter the dimensions, and choose the unit for each measurement. The converter compares surface area so you can see whether the replacement is smaller, larger, or broadly similar. Measure the inside cooking surface rather than the outside rim. For a rectangular pan, enter length and width; for a round pan, enter diameter; for a square pan, enter one side. Keep the same unit within each set of dimensions and let the tool perform the comparison.
Method and practical checks
Round area is calculated from π multiplied by radius squared. Square area uses side multiplied by side, and rectangular area uses length multiplied by width. The tool converts supported metric and imperial dimensions before comparing the areas. Area is only a planning aid: pan depth, material, colour, recipe volume, oven temperature, and the amount of batter also affect baking time and doneness. A deeper replacement may need a different filling level or a longer bake, so check the recipe as it cooks and follow its food-safety instructions.
After comparing areas, compare the depth and capacity of the pans as well. Fill a replacement pan only as high as the recipe safely permits, because a smaller or deeper vessel can change the way heat reaches the centre. Place the pan where the oven can circulate heat and begin checking at the recipe’s stated time. The converter does not account for the shape of corners, the exact volume of batter, or differences between ovens, so the visual and physical checks in the recipe still matter.
Frequently asked questions
Does equal area guarantee equal baking time?
No. Depth, material, recipe volume, and oven conditions can change the result.
Which dimensions should I measure?
Measure the inside cooking surface and enter the dimensions requested for the selected shape.