Food & Cooking
Cake Pan Converter
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How to use it
Using the cake pan converter
- 01
Pick both pans
Choose the diameter your recipe was written for and the pan you actually own.
- 02
Read the factor
Multiply every ingredient; flour, butter, eggs, leaveners; by the displayed factor.
- 03
Watch depth and time
Shallower batters bake faster; start checking doneness early and trust the toothpick over the timer.
Good to know
Why squares of diameter, not diameter itself
A 9-inch pan looks only marginally wider than an 8-inch, yet holds over a quarter more batter; area grows with the square. Recipes fail during pan swaps precisely because intuition tracks width while chemistry cares about volume.
Bake time moves opposite to factor
More batter usually means longer baking, but shallower spreads finish sooner. After converting, judge by visual cues; edges pulling away, center springing back; and begin testing well before the original time.
Eggs complicate clean factors
Multiplying 1.266 × 2 eggs gives 2.53; you cannot crack half an egg. Beat the eggs, weigh them, then use the needed fraction; most cakes forgive a few grams either way.
How it's calculated
The math behind this calculator
Factor = (New diameter ÷ Old diameter)² (π cancels)Round pan capacity scales with π·d²/4, so switching diameters multiplies required batter by the square of the diameter ratio; the π terms cancel entirely. A factor above one means the new pan is hungrier; below one, scale down to avoid overflow.
Assumptions & limitations
- Both pans are the same depth; deeper pans also want more batter.
- Leavening behaves linearly across the sizes offered here.
- Fill any pan no more than two-thirds full regardless of the factor.
Worked example
Moving an 8-inch recipe to a 9-inch pan: (9/8)² = 1.266, so multiply every ingredient by 1.266; about an extra quarter batch.
FAQ
Frequently asked questions
- How much more batter does a 9-inch pan hold than 8-inch?
- (9/8)² ≈ 1.266; about 27% more. That single jump explains sunken centers when recipes are poured unadjusted.
- Does pan height matter?
- Yes for bake time more than volume here. This tool compares diameters; deeper pans need the two-thirds fill rule respected above all.
- Can I convert between square and round pans?
- Compare areas directly: an 8-inch square holds more than an 8-inch round (64 vs ~50 sq in); scale by the actual areas.
- What about cupcakes?
- A standard 8-inch round layer yields roughly 22–24 cupcakes by volume; divide your converted batter across lined tins two-thirds full.
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