Baking Pan Size Converter
Work out whether a recipe fits the pan you own, and how much to scale the batter when it does not.
What you need
0.54
Scale the recipe by — Below about 0.8 or above 1.25, adjust the batter rather than accepting the difference.
- Area of the pan the recipe calls for
- 117.0 sq in
- Area of the pan you have
- 63.6 sq in
Estimates for planning. Confirm quantities with your supplier before ordering — see the assumptions below for the figures used.
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The pans the common substitutions above assume. Quantities come straight from your calculation above — check them against your supplier's pack sizes before ordering.
Tools & equipment
9 by 13 in baking pan
The size most American recipes are written for.
Round cake pans
Two 9 in rounds come to roughly the same area as one 9 by 13.
Half sheet pan
13 by 18 in, almost exactly twice the area of a 9 by 13.
Oven thermometer
Home ovens routinely run 25 degrees off the dial, which matters more once you have changed pan.
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How to use the baking pan size converter
A recipe written for a 9 by 13 inch pan will overflow an 8 inch square and will bake thin and dry in a half sheet. What matters is the area of the pan, because that is what sets how deep the batter sits. Enter the pan the recipe calls for and the pan you actually have.
Reading the scale factor
A factor of 1.0 means the pans hold the same batter depth and you can bake the recipe unchanged. Above 1.0 the new pan is larger, so the same batter spreads thinner — either scale the recipe up by that factor or accept a flatter, faster-baking result.
Below 1.0 the pan is smaller and the batter will sit deeper. This is the direction that causes trouble: overflow in the oven, and a centre that is still raw when the edges are done. Under about 0.8, scale the recipe down rather than hoping.
Common pans by area
8 inch round is about 50 square inches, 9 inch round about 64, and 10 inch round about 79. An 8 inch square is 64, a 9 inch square is 81, and the standard 9 by 13 is 117.
A quarter sheet pan is roughly 9 by 13, which is why the two are so often interchangeable. A half sheet at 13 by 18 is about 234 square inches — exactly twice a 9 by 13, and a useful thing to remember when doubling.
What this calculator assumes
Every estimate depends on figures that vary by supplier and conditions. These are the ones used here, so you can sanity-check the result against your own quote.
- Pans are compared by base area, which assumes both are a similar depth. That holds for the usual run of cake pans, square pans and sheet pans at 2 inches or so.
- Measure across the inside of the pan at the top, not the outside, and not the base — most pans slope slightly.
- A scale factor between about 0.8 and 1.25 can usually be ignored for sturdy bakes such as brownies and sheet cakes. You will get a thinner or thicker result and a different bake time.
- Bundt, tube and other shaped pans are rated by volume rather than area, because the batter climbs a central column. Compare those by how much water they hold instead.
- Bake time is not part of the scale factor. Batter in a shallower pan bakes faster and batter in a deeper one bakes slower, regardless of the total quantity.
Frequently asked questions
Can I use a 9 inch round pan instead of an 8 inch square?
Yes, near enough. An 8 inch square is 64 square inches and a 9 inch round is about 63.6, so the batter depth is effectively identical and the bake time barely changes. This is one of the safest substitutions in baking.
What can I use instead of a 9 by 13 inch pan?
A 9 by 13 is 117 square inches. Two 9 inch rounds come to about 127 square inches together, which is close, and two 8 inch squares give 128. A single 8 inch square is only 64 and will overflow badly — roughly half the recipe is all it can take.
How do I adjust the baking time for a different pan?
Go by batter depth, not by the scale factor. Shallower batter bakes faster: start checking 10 to 15 minutes before the stated time. Deeper batter needs longer and a slightly lower oven, often 25 degrees Fahrenheit down, so the outside does not set long before the middle does.
Why compare pans by area rather than volume?
Because for pans of similar depth the area is what decides how deep the batter sits, and depth is what drives both rise and bake time. Volume only becomes the right comparison for shaped pans such as bundt and tube tins, where the geometry is not a simple prism.
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