How pan conversion works
To keep the batter or dough the same depth, scale the recipe by the ratio of the pan areas:
factor = your pan area ÷ recipe pan area
- Round pan area = π × (diameter ÷ 2)²
- Square pan area = side²
- Rectangular pan area = length × width
Use the same unit (inches or centimeters) for both pans; the factor doesn't depend on the unit.
Examples
- A 9" round (63.6 sq in) and an 8" square (64 sq in) are practically the same: no scaling needed.
- Two 9" rounds (127 sq in) to one 9 × 13" pan (117 sq in): multiply by about 0.92.
- An 8" round (50.3 sq in) to a 10" round (78.5 sq in): multiply by about 1.56.
Baking time and temperature
If the depth stays the same, baking time stays similar, but larger pans can take a little longer to set in the middle. Check doneness early and use your usual test (a skewer, internal temperature, or spring-back). If you don't scale and the batter is deeper, lower the temperature slightly and bake longer.
Frequently asked questions
Is a 9-inch round the same as an 8-inch square?
Almost exactly: a 9" round is about 63.6 square inches and an 8" square is 64 square inches.
How do I convert a recipe from a 9×13 pan to two 8-inch rounds?
A 9×13 is 117 sq in; two 8" rounds are about 100.5 sq in, so multiply the recipe by about 0.86, or keep it the same and fill the pans a little deeper.
Do I need to change the baking time?
Keep the time similar if the batter depth is the same, but start checking a few minutes early. Deeper batter needs longer and often a slightly lower temperature.