Example 01
8-inch round to 9-inch round
The areas are about 50.3 in² and 63.6 in². The multiplier is 1.27×, so increase every ingredient by roughly 27%.
Scale with confidence
Baking Pan Conversion Calculator
Switch pan sizes or shapes without guessing. Compare surface areas and get a clear multiplier for your recipe.
Worked examples
Common pan swaps, explained
Example 02
9-inch round to 8-inch square
The areas are about 63.6 in² and 64 in². They are approximately equivalent, so the original recipe should fit without meaningful scaling.
Example 03
8-inch square to 9 × 13-inch
The areas are 64 in² and 117 in². Use about 1.83× the recipe, while checking that the pan depth and capacity are suitable.
How pan conversion works
The calculator compares the top surface area of each pan. A round pan uses π × radius², a square pan uses width², and a rectangular pan uses width × length. Measurements are converted internally, so inches and centimetres can be mixed.
The target area is divided by the original area to make the recipe multiplier. Multiply each scalable ingredient by that number, but use judgement for items such as whole eggs and leavening.
What area cannot tell you
Two pans with equal surface area can have different depths and capacities. Do not rely on area alone if the new pan is unusually shallow, and do not use this calculator as a guaranteed baking-time converter.
Questions answered
Pan conversion FAQ
How do I convert an 8-inch cake recipe to a 9-inch pan?
A 9-inch round pan has about 27% more surface area than an 8-inch round pan. Multiply every ingredient by 1.27 and keep the batter depth similar.
Can I use a square pan instead of a round pan?
Yes. Compare the pans by surface area and scale the recipe if needed. An 8-inch square pan is close in area to a 9-inch round pan.
Does changing the pan size affect baking time?
It can. Wider or shallower batter often bakes faster, while deeper batter may take longer. Start checking early and judge doneness rather than relying on a fixed converted time.
How full should I fill a cake pan?
As a general rule, do not fill a cake pan more than about two-thirds full unless the recipe specifically says otherwise.
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