Baking Pan Converter

Tin in the recipe

Diameter or side, cm

Your tin

Diameter or side, cm

Side height, cm

Only needed for the volume.

Result

Multiply every ingredient by0.694
Change in quantity, %-30.6%
What happens to the baking timethe batter sits deeper — add 5–15 minutes and cover with foil
Recipe tin area, cm²452.4
Your tin area, cm²314.2
Volume of your tinthe new pan holds 1.88 l

It is the area that matters, not the width

Works out the factor to multiply every ingredient by when your tin is a different size or shape from the one in the recipe, and what that does to the baking time.

The classic mistake is scaling by diameter. A 24 cm tin is not 1.2 times bigger than a 20 cm tin, it is 1.44 times bigger: area grows with the square of the size. That is exactly why batter meant for 24 cm rises like a wall in a 20 cm tin and stays raw in the middle.

This calculator takes the base area of both tins and hands back one multiplier for the whole ingredient list. Round tins can be compared with square or rectangular ones — area puts them on the same footing.

What this calculator shows

The factor to multiply every ingredient in the recipe by
How much the quantity of batter changes, as a percentage
Which way the baking time moves, and the volume of your tin

What to keep in mind

Scaling uses the base area: the side height does not change the quantity of batter until it starts overflowing.
This works for sponges, loaf cakes and tarts. Puff and shortcrust pastry are rolled to a thickness set by the recipe and scale differently.

FAQs

Is a 24 cm round the same as a 20 cm square?

Nearly. A 24 cm circle is 452 cm², a 20 cm square is 400 cm². The 13% gap is one most home bakers happily ignore.

How do I adjust the baking time?

By depth. Thinner batter is done 5 to 10 minutes early; deeper batter wants 5 to 15 minutes more and a sheet of foil over the top.

Can I use a tin that is too big?

You can, but the cake comes out low and a little dry. Past a factor of about one and a half, increase the batter rather than spreading the old quantity thinner.

What about the temperature?

Leave it. Deeper batter needs longer at the same temperature, not a hotter oven — turn the oven up and you get a crust outside and raw batter inside.

Worked example

A 24 cm recipe in a 20 cm tin

Input: Round 24 cm → round 20 cm

Output: Factor 0.69, 30.6% less of everything

Note: Keep the quantities as written and the batter sits half again as deep: the centre never cooks through while the edges have time to darken.

Useful links

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Baking Pan Converter

Result

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Useful links