How to Convert a Recipe Between Cake Pan Sizes
Every baking pan holds a different amount of batter, so swapping pans without adjusting the recipe is the most common reason cakes come out flat, overflow the rim, or bake unevenly. This cake pan converter does the math for you: it compares the capacity of your recipe's pan with the pan you actually own and tells you exactly what to multiply every ingredient by — whether you're converting an 8-inch round to a 9x13, a 9x13 to two round layers, or a layer cake recipe into cupcakes.
The conversion is based on pan volume. A standard 8-inch round pan holds about 6 cups brim-full, while a 9-inch round holds 8 cups — that's why an 8-inch recipe baked in a 9-inch pan comes out noticeably thinner. Our capacities follow published test-kitchen measurements for every common pan: round layers from 6 to 10 inches, square and rectangular pans including the classic 9x13, loaf pans, Bundt and tube pans, springforms, sheet pans, and standard cupcake tins.
Why batter depth matters more than pan size
Two pans can hold the same volume yet bake very differently. What actually determines bake time is how deep the batter sits. Deeper batter needs a lower temperature and a longer bake so the center sets before the edges dry out; shallower batter bakes faster and is done sooner. That's why this tool calculates the batter depth in both pans and adjusts its time-and-temperature guidance accordingly — something a simple conversion chart can't do.
Quick reference: cake pan capacities
| Pan | Brim-full capacity | Closest substitute |
|---|---|---|
| 6" round × 2" | 4 cups | 8½×4½" loaf (close) |
| 8" round × 2" | 6 cups | 8½×4½" loaf, 12 cupcakes |
| 9" round × 2" | 8 cups | 8" square, 9×5" loaf |
| 8" square × 2" | 8 cups | 9" round |
| 9" square × 2" | 10 cups | 10" round, 9" springform |
| 9×13" × 2" | 14 cups | two 9" rounds, 10" Bundt |
| 9×5" loaf | 8 cups | 9" round, 8" square |
| 10" Bundt | 12 cups | 9×13", two 8" rounds |
Tips for a successful pan swap
Fill the new pan between one-half and two-thirds full — never more, or the rising cake will overflow. When the multiplier lands on an awkward egg count, round to the nearest whole egg and hold back a tablespoon of liquid if the batter looks loose. Dark or glass pans brown faster than light aluminum, so drop the oven temperature by 25°F for those. And whatever the math says, trust the toothpick: every oven and every batter behaves a little differently, so start testing for doneness a few minutes before the adjusted time. Working with an odd or custom-sized pan that isn't in the list? Choose Custom size… in either menu above and enter its dimensions — the converter estimates the capacity from the geometry. For the raw volume of a single pan, the pan volume calculator shows it in cups, millilitres and litres — and if the cake is for an event, the cake serving calculator tells you how many people each size feeds.
The conversions bakers ask for most
- 9x13 to 8x8: an 8x8 holds about half a 9x13 — halve the recipe (or make 1½× and bake two 8x8s).
- 8-inch round to 9-inch round: the 9-inch holds ~25% more, so the same batter bakes noticeably thinner and faster — multiply by 1¼ to keep the height.
- Two 9-inch rounds to a 9x13: almost exactly even — use the layer-cake recipe as-is and start checking a few minutes earlier.
- 9x13 to a Bundt: a standard 10–12 cup Bundt takes the full 9x13 batter, but fill it no more than ¾ and expect a longer bake at the same temperature.
Don't know your pan's capacity? Measure it with water
The definitive answer for an odd or unlabeled pan takes one minute: set it in the sink and fill it with water one measured cup at a time, right to the brim, counting as you go. That brim-full number is exactly what this converter's capacity figures mean — compare it to the chart above and use the closest match. (For a decorative Bundt, this is the only reliable method; manufacturers vary wildly.)