How to convert a cake recipe to a different pan size

The one rule: batter follows volume

A cake recipe is really a volume of batter. Move that batter to a pan with the same capacity and nothing changes; move it to a bigger or smaller pan and you scale every ingredient by the ratio of the two capacities. That's the entire trick:

multiplier = new pan's capacity ÷ original pan's capacity

An 8″ round layer pan holds 6 cups brim-full; a 9″ round holds 8. Moving a recipe from the 8″ to the 9″ means multiplying every ingredient by 8/6 = 1.33 — 1⅓×. The capacities we use are published pan data (King Arthur and Wilton charts), not estimates, and each one is pinned by an automated test.

Do it live

Pick your two pans — the converter shows both drawn to scale, the multiplier, and the time and temperature adjustments from the sections below. It handles custom sizes too.

Common conversions, worked out

These figures are computed by the same tested engine as the calculator above — they cannot drift out of sync with it.

Why time and temperature change (it's depth, not size)

Bake time doesn't track pan size — it tracks batter depth. The center of a deep layer is insulated by the batter above and beside it, so it needs longer to reach a set crumb; run the oven hot and the edges dry out first. The working rules, which the calculator applies from the actual computed depths:

• Batter noticeably deeper (more than ~20% deeper than the original): drop the oven 25°F and expect 15–25% more time. Start testing at the original time.
• Batter noticeably shallower: keep the temperature and start checking 10–15% early. Thin layers overbake fast.
• Similar depth: bake as written, testing five minutes early. Converting between pans of similar geometry (8″ round → 9″ round with a scaled recipe) barely moves the clock.

"Done" is a skewer with moist crumbs, an internal temperature around 200–210°F, and edges just pulling from the pan — trust those over any clock, converted or not.

Conversions to treat with care

• Angel food and chiffon → anything. These foam cakes climb the ungreased walls of a tube pan and hang upside-down to cool. In a greased round or loaf they collapse. Don't convert them; bake them in the pan they were written for.
• Anything → Bundt or tube. The center core changes how heat reaches the batter, and intricate Bundt patterns punish delicate cakes. Sturdy butter and pound cakes convert well; light sponges don't. A 10″ Bundt holds 12 cups — fill it two-thirds at most.
• Cheesecake → regular pans. You'll never get it out. Springform or a lined pan with slings only.
• Big multipliers. Past roughly 2×, mix in batches: creaming, aeration and even flour hydration behave differently in one giant bowl, independent of the pan math.

Every pan we track

Capacities are brim-full, from published manufacturer and test-kitchen charts. Recipes normally fill a pan about two-thirds full.