Baking Pan Size Converter
Baking pan size converter — pick the pan a recipe was written for and the pan you want to use (round, square or rectangular) and get the exact factor to scale every ingredient by, so your batter fits. Works in inches or centimetres. Runs in your browser.
Baking Pan Size Converter
Recipe’s pan
Your pan
How to Use the Baking Pan Converter
Choose your unit
Pick inches or centimetres to match how your pans are labelled.
Enter the recipe’s pan
Set the shape and size the recipe was written for.
Enter your pan
Set the shape and size of the pan you actually want to use.
Scale the recipe
Multiply every ingredient by the factor shown, and adjust the bake time for the new depth.
Swapping Baking Pans Without Ruining the Recipe
Every baker hits this problem: the recipe calls for a pan you do not own, and the one in the cupboard is a different size or shape. Guessing leads to batter overflowing the sides or a thin, overcooked disc. The fix is a single number — the ratio of the two pans’ surface areas — and that is exactly what this converter computes. Because batter sits across the bottom of a pan, the amount needed to reach a given depth depends on the pan’s area, not its width. So you find the area of the pan the recipe was written for, the area of the pan you want to use, and divide one by the other to get the factor to multiply every ingredient by.
The crucial, counter-intuitive point is how fast area grows. A round pan’s area depends on the square of its radius, so a pan that looks only a little wider holds a lot more: a nine-inch round has about twenty-seven per cent more capacity than an eight-inch round, even though it is only an inch bigger across. Comparing widths would tell you to add a few per cent; comparing areas tells you the truth. The same logic lets the tool convert between shapes — a round and a square of the same nominal size enclose different areas — so any combination of round, square and rectangular pans gives a correct factor. Units do not matter for that factor, because it is a ratio of two areas measured the same way and the units cancel; they only affect the areas shown for reference.
Two practical notes turn the number into a good bake. First, scaling keeps the ingredient proportions identical, so the batter itself is unchanged — what changes is its depth in the new pan, and depth drives timing. Keep the oven temperature the same, but check a shallower bake earlier and give a deeper one longer, judging by the usual tests rather than the original recipe’s clock. Second, respect the two-thirds rule: however the maths works out, do not fill a cake pan more than about two-thirds full, or it will climb over the rim as it rises — if a scaled-up recipe would over-fill your pan, reach for a larger or deeper one, or bake the surplus as cupcakes. Everything is computed in your browser from simple geometry, so nothing you enter leaves your device.
Pans scale by area, not width — which is why a pan an inch wider can need a quarter more batter than you’d guess.
10 Facts About Baking Pans
Pan capacity scales with area, not width.
A 9-inch round holds ~27% more than an 8-inch round.
Round area = π × radius²; square = side².
A round and a square of the same width differ in area.
Scale every ingredient by the same factor.
Don’t fill a pan more than about two-thirds.
Shallower batter bakes faster; deeper bakes slower.
Keep the oven temperature the same — just adjust time.
Loaf and bundt pans are measured by volume too.
This calculator runs in your browser — nothing is uploaded.
Frequently Asked Questions
- Work out the area of the pan the recipe was written for and the area of the pan you want to use, then divide the new area by the original. That ratio is the factor you multiply every ingredient by. The calculator does this for you and shows the factor, so a recipe scaled by 1.27, for example, needs 27% more of everything.
- Because batter spreads across the bottom of the pan, and the amount it takes to reach a given depth depends on the surface area, which grows with the square of the width. A pan that is only a little wider holds substantially more, so comparing widths directly would badly underestimate how much extra batter you need.
- A round pan’s area is π times the radius squared, where the radius is half the diameter you enter. A square or rectangular pan’s area is simply its length times its width. The tool asks for the right dimensions depending on the shape you choose.
- Yes — that is one of the most useful cases. A round and a square pan of the same nominal size hold different amounts because their areas differ, and the calculator handles any combination of round, square and rectangular pans, giving you the correct scale factor between them.
- Only for displaying the areas. The scale factor itself is a ratio of two areas measured in the same unit, so the units cancel out and the factor is the same whichever you choose. Pick whichever matches how your pans are labelled.
- Generally no — keep the temperature the same and adjust the time instead. If the new pan spreads the batter thinner, it will bake faster, so start checking earlier; if it makes the batter deeper, it will take a little longer. The depth of the batter, not the recipe, drives the timing change.
- Yes. Even with the right total volume, you should not fill a cake pan more than about two-thirds, or it may overflow as it rises. If a scaled-up recipe would over-fill your pan, use a larger or deeper pan, or bake the excess separately as cupcakes or a small extra cake.
- It works on the flat-area basis, which is a good approximation for standard cake pans. Loaf, bundt and tube pans are often specified by volume because of their shape, so for those it is more accurate to compare capacities in cups or millilitres if the manufacturer provides them. Use the area method as a reasonable starting estimate otherwise.
- Scaling keeps the ingredient ratios identical, so the batter is the same; what changes is the depth and therefore the bake. Very large changes in depth can affect how evenly a cake bakes and rises, so for big jumps it is often better to use a pan closer in proportion, or split the batter across two pans.
- Completely free, with no account or usage limit. It runs entirely in your browser, collects no data, and works offline once the page has loaded.
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