How do I substitute one cake pan for another?

Compare the floor area of the two pans, not their widths. A round pan area is π times the radius squared; a square or rectangle is length times width. If the new pan has more area, the batter sits shallower and bakes faster; less area means deeper and slower. The converter gives the exact area ratio and what to do about it.

Is an 8-inch square the same as a 9-inch round?

They are very close. An 8-inch square is 64 square inches and a 9-inch round is about 63.6 square inches, so you can usually swap them with no change to the recipe. This is one of the handiest pan swaps to know, and the converter confirms it for any pair you pick.

Do I need to change the bake time?

Often, yes. A shallower batter in a larger pan cooks faster, and a deeper batter in a smaller pan cooks slower. The temperature usually stays the same. Start checking for doneness earlier or later than the recipe says depending on which way the depth changed, and use the toothpick test rather than the clock.

Does this work offline and is anything sent to a server?

The calculation runs entirely in your browser, so nothing you type is sent anywhere, and once the page has loaded it keeps working with no connection. There is no sign-up and no limit on how many conversions you make.

Baking Pan Converter

Swap one baking pan for another using surface area. When you change pans, the batter depth and the bake change with the floor area, not the width. Pick the pan your recipe wants and the pan you have, and see the area ratio plus how to adjust the recipe and bake time.

Ingredient-aware accuracy
100% free
No sign-up, no app
Instant as you type
Works offline after first load

Read the guide: Baking Pan Size Conversions

Recipe wantsYou have

Recipe pan area

63.6 sq in

Your pan area

64 sq in

Scale recipe by

×1.01(+1%)

These pans are close in size — use the recipe as written.

Based on floor area: round pans use π × radius², square and rectangle pans use length × width. The temperature usually stays the same; watch the bake, since depth changes how fast it cooks.

How to use it

1
Set the recipe pan

Choose the shape and size the recipe calls for: round, square or rectangle.
2
Set your pan

Choose the pan you actually have. The converter compares their surface areas.
3
Read the adjustment

See the area ratio and plain-language guidance on scaling the recipe and watching the bake.

When it comes in handy

Using the pan you own

A recipe wants a 9-inch round but you have an 8-inch square. See whether they are close enough to swap.

Scaling batter to fit

Work out how much to scale a recipe up or down so a different pan is filled to the right depth.

Avoiding overflow

Check that batter for one pan will not overflow a smaller one before you pour it in.

Instant, exact & 100% in your browser

The conversion runs right here in your browser using exact, standard factors. Nothing you type is sent to a server, there is no sign-up and no limit, and once the page has loaded it keeps working even with no connection.

Frequently asked questions

How do I substitute one cake pan for another?: Compare the floor area of the two pans, not their widths. A round pan area is π times the radius squared; a square or rectangle is length times width. If the new pan has more area, the batter sits shallower and bakes faster; less area means deeper and slower. The converter gives the exact area ratio and what to do about it.
Is an 8-inch square the same as a 9-inch round?: They are very close. An 8-inch square is 64 square inches and a 9-inch round is about 63.6 square inches, so you can usually swap them with no change to the recipe. This is one of the handiest pan swaps to know, and the converter confirms it for any pair you pick.
Do I need to change the bake time?: Often, yes. A shallower batter in a larger pan cooks faster, and a deeper batter in a smaller pan cooks slower. The temperature usually stays the same. Start checking for doneness earlier or later than the recipe says depending on which way the depth changed, and use the toothpick test rather than the clock.
Does this work offline and is anything sent to a server?: The calculation runs entirely in your browser, so nothing you type is sent anywhere, and once the page has loaded it keeps working with no connection. There is no sign-up and no limit on how many conversions you make.