How to use this calculator
Enter the pan the recipe was written for, then enter the pan you actually want to use. The calculator computes the volume of each pan and gives you a scaling factor — the number you multiply every ingredient by. It also tells you whether to adjust time and temperature based on how the batter depth changes.
The math is straightforward but easy to get wrong by hand: round pans use π × radius² × depth, while square and rectangular pans are length × width × depth. Bundt and tube pans are trickier because of the center hole — we estimate them at 75% of the equivalent solid round pan, which lines up well with manufacturer specs.
Why pan size matters more than you think
If you pour the same amount of batter into a smaller pan, the batter sits taller. That means the outside cooks faster than the inside, and your cake comes out either burnt on top or raw in the middle. If you pour it into a larger pan, the batter spreads thin, dries out, and comes out flat.
The fix is matching by volume. A 9-inch round pan (around 9.5 cups) is roughly the same as an 8-inch square pan (around 9 cups). You can swap them with no scaling. But a 9x13 pan holds nearly twice that — using your 9x13 for an 8-inch round recipe means your cake is half as tall as it should be.
How to adjust time and temperature
If your pan is shallower (batter spreads thinner)
Bake at the same temperature, but check for doneness 25-33% earlier. A 30-minute recipe might be done in 20 minutes. Use a toothpick.
If your pan is deeper (batter sits taller)
Drop the temperature by 25°F (15°C) and add 10-25% more time. The lower temperature lets the center cook through before the edges set. This is especially important for cakes, brownies, and dense quick breads.
If pan depth is similar
Keep the temperature and the time roughly the same. Start checking a few minutes early just in case.
Common pan capacities (reference)
| Pan | Volume (cups) | Cu inches |
|---|---|---|
| 8" round × 2" | 6.0 | 100 |
| 9" round × 2" | 9.5 | 127 |
| 10" round × 2" | 11.5 | 157 |
| 8" square × 2" | 9.0 | 128 |
| 9" square × 2" | 11.5 | 162 |
| 9 × 13" × 2" | 15.5 | 234 |
| 8.5 × 4.5" loaf × 2.5" | 6.0 | 96 |
| 9 × 5" loaf × 2.75" | 8.0 | 124 |
| 9" springform × 2.5" | 11.0 | 159 |
| 10" bundt × 3.5" | 10.0 | 206 |
| 15 × 10" jelly roll × 1" | 10.5 | 150 |
When NOT to substitute pans
Some recipes really do need their specified pan. Angel food cakes need a tube pan because they climb up the center column to rise. Cheesecakes need springform pans because you can't flip them out. Brownies are forgiving; layer cakes are less so.
If you're attempting an unusual swap (loaf pan for a round cake, sheet pan for a brownie), the structural integrity might suffer even if the volume math works out. When in doubt, halve the recipe and use a smaller pan rather than scaling up to fit a wildly different shape.
Frequently asked questions
Can I substitute a 9x13 pan for an 8x8?
A 9x13 pan holds nearly twice the volume of an 8x8 (about 234 vs 128 cubic inches). To use a 9x13 for an 8x8 recipe, double the recipe. To use an 8x8 in place of a 9x13, halve it.
How do I adjust baking time when I change pan size?
Shallower pan: reduce time by 25-33% and check early. Deeper pan: increase time by 10-25% and drop temperature 25°F. Always verify with a toothpick.
Should I change the oven temperature?
Usually no. The exception is when the new pan makes a much thicker batter — drop 25°F so the center cooks before the edges burn.
Can I use a round pan instead of a square pan?
Yes. Match by volume. A 9-inch round pan is similar to an 8-inch square. The calculator shows you the scaling factor either way.
How is bundt pan capacity calculated?
Bundt pans have a center tube, so capacity is roughly 75% of a solid round pan of the same outer diameter. Most 10-inch bundt pans hold 10-12 cups.