Baking pan size converter
Change the tin and we tell you what to multiply the recipe by.
Your inputs
Your inputs are processed on your device and are not sent to a server.
Example loaded. You can change any value.
There is no figure yet: nothing is calculated until you ask for it.
- Enter your measurements.
- Check the units and the assumptions.
- Press Calculate, or load the example.
Rather see a worked case? Press “Load example” and change any value afterwards.
Next step
Changing tin without scaling the ingredients leaves the cake flat or raw.
Where each number comes from Conversion constants are exact; densities and coverage rates come from cited sources; everything else is an assumption you can change. Methodology · Sources and updates
How to use it
- Choose the shape and size of the tin in the recipe.
- Choose the shape and size of the tin you actually have.
- If you know the heights, enter them: we compare by volume.
- The result gives the factor to multiply the recipe by.
How it is calculated
Two tins are compared either by area or by volume, and the difference matters:
If you only enter the base dimensions we compare by area, which assumes the batter sits at the same depth in both. Enter the heights too and we compare by volume, which is more accurate when the tins have different depths.
A surprising figure: an 8 in round tin and an 8 in square tin are not equivalent. The square has 27 % more area, because the circle gives up the corners.
Worked example
The recipe is for an 8 in round tin and you have an 8 in square:
- Round area: π x 4² = 50.3 sq in
- Square area: 8 x 8 = 64 sq in
- Factor: 64 / 50.3 = 1.27
You need 27 % more batter. Without it, the cake comes out shallower and bakes sooner than the recipe says.
Good to know
- Baking time changes. A wider tin bakes faster, a deeper one slower. Start checking 10 minutes before the stated time.
- Do not fill past two thirds. Chemically leavened cakes rise a lot; going higher ends with batter on the oven floor.
- Factors between 0.9 and 1.1. Swap directly with no recipe changes, just watch the timing.
- Springform tins measure differently. Measure the inside, not the outer rim.
Frequently asked questions
Is an 8 inch round tin the same as an 8 inch square?
No. The square has 27 % more area. To use it with the same recipe you need to multiply the quantities by 1.27, or accept a shallower cake.
What square tin matches a 9 inch round?
About 8 inches square, which has practically the same area (64 sq in against 63.6 sq in).
Does it compare by area or by volume?
By area if you only give the base dimensions, which assumes the same batter depth. By volume if you also enter the heights, which is more accurate.
Do I need to change the baking time?
Yes. A wider tin spreads the batter thinner and bakes sooner; a narrower, deeper one takes longer and may need a lower temperature.
How full should the tin be?
Up to about two thirds of its height for chemically leavened batters, a little less if the mixture rises a lot.