How much should I multiply a 15 cm recipe to make it in an 18 cm pan?

1.44×. For round pans, base area changes with the square of the diameter ratio, so (18 ÷ 15)² = 1.44. A 2-egg recipe becomes 2.88 eggs, so about 3 eggs (or 144 g of beaten egg). Conversely, making an 18 cm recipe in a 15 cm pan takes about 0.69×.

How do Japanese cake sizes relate to diameter and servings?

Size 1 = 3 cm in diameter, so as a guide size 4 = 12 cm (2–4 people), size 5 = 15 cm (4–6), size 6 = 18 cm (6–8), size 7 = 21 cm (8–10), and size 8 = 24 cm (10–12). In the “Size & ratio chart” tab you can also check recipe ratios based on size 5 and egg counts for sponge cakes.

How do I convert a round-pan recipe to a square pan?

To bake at the same thickness, convert by the ratio of base areas. Making an 18 cm round-pan recipe (about 254 cm²) in an 18 cm square pan (324 cm²) is about 1.27×, and in a 15 cm square pan about 0.88×. An 18 cm round pan has about the same area as a 16 cm square pan.

Can I make a loaf-pan recipe in a round or muffin pan?

Yes. Since the pans differ in thickness, convert by batter amount (volume). A recipe for an 18 × 8 cm loaf pan is about 1.4× for a 15 cm round pan, or about 8 standard muffins (7 cm top diameter). Moving to muffin or small pans shortens the baking time.

How do I make a 17 cm chiffon cake recipe in a 20 cm pan?

About 1.68× is a guide. A chiffon pan’s height changes with its diameter, so it’s the ratio of volumes (nearly the cube of the diameter ratio). A recipe with 3 yolks and 4 whites becomes about 5 yolks and 6–7 whites. For a 23 cm pan it’s about 2.6×.

The calculation gives a fractional number of eggs like 2.9. What should I do?

Weighing beaten egg is the reliable way. A medium egg is about 50 g net (yolk 20 g, white 30 g), so for 2.9 eggs use 145 g of beaten egg. For batters where whipping eggs matters, like sponge or chiffon, you can round the eggs up and increase the other ingredients accordingly.

How much longer should I bake when using a bigger pan?

As a guide, keep the temperature the same as the original recipe or lower it by 10°C, and extend the baking time by 5–15 minutes. For a smaller pan, shorten it by 5–10 minutes. The thicker the batter, the harder it is for the center to cook, so cover with foil if the top starts to burn, and bake until a skewer comes out clean.

How are tablespoons and teaspoons converted?

It converts to teaspoons with 1 tbsp = 3 tsp, rounds to 1/4 increments, and then shows combinations like “2 tbsp and 1/2 tsp”. Amounts under 1/4 spoon are hard to measure, so adjust things like vanilla oil and salt to taste.

Cake Pan Size Converter | Recipe Amounts When Changing Pans, like 15 cm → 18 cm

Just choose the recipe’s pan and the pan you want to use, and it calculates how much to multiply the ingredients. Between round and square pans it uses the ratio of base areas, such as 1.44× for 15 cm → 18 cm or 0.69× for 18 cm → 15 cm, and across loaf, chiffon, muffin, and sheet pans it uses the ratio of batter volume. Paste your ingredients to rewrite g, mL, egg counts, and spoons all at once to match the ratio, with fractional eggs shown in grams of beaten egg. It also includes baking time guidance and a chart of Japanese cake sizes (gō), servings, and ratios.

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About Cake Pan Size Converter | Recipe Amounts When Changing Pans, like 15 cm → 18 cm

The cake pan size converter calculates how much to multiply your ingredients when the pan in a recipe differs from the one you have. It supports 7 types (round pans / rings, square pans, loaf pans, chiffon pans, muffin pans, sheet pans for roll cakes, and a volume you specify), using the ratio of base areas between round and square pans (keeping batter thickness the same) and the ratio of batter volume across types. Paste the ingredients to rewrite g, mL, egg counts, tablespoons/teaspoons, and cups according to the ratio all at once, with fractional eggs shown as grams of beaten egg. It also has charts of Japanese cake sizes (gō) and servings, ratios between round and chiffon pans, and egg counts for sponge cakes.

How to use Cake Pan Size Converter | Recipe Amounts When Changing Pans, like 15 cm → 18 cm

1Choose a similar combination from “Common conversions”, or enter the type and dimensions of the “Recipe’s pan (original)”
2Enter the type and dimensions of the pan you have in “Pan you want to use” (diameter for round pans, length × width for square and sheet pans, top inner dimensions for loaf pans)
3Check the ratio shown (e.g. ×1.44 for 15 cm → 18 cm) and the comparison of base areas and volumes
4Paste the recipe ingredients one per line as “ingredient amount”, check the rewritten amounts, and press “Copy converted ingredients”
5Check the baking time and temperature guide, and test doneness with a skewer

Great for

Make a 15 cm (size 5) shortcake recipe in an 18 cm (size 6) round pan
Reduce an 18 cm recipe to about half for a small 12 cm or 15 cm pan
Bake a round-pan recipe in a square pan for a cake that’s easy to slice
Move a loaf-pan recipe to a round or muffin pan and find out how many it makes
Scale up a chiffon cake recipe from 17 cm to a 20 cm or 23 cm pan
Adjust a roll cake recipe for a 28 cm sheet pan to a 25 cm or 30 cm one
Find out how many grams of beaten egg to use when you get a fractional count like 2.9 eggs
Check the diameter and number of servings from a birthday cake’s size number

Good to know

Ratios between round and square pans use the ratio of base areas (for round pans, the square of the diameter ratio), assuming batter thickness stays the same. 15 cm → 18 cm is (18 ÷ 15)² = 1.44×, 18 cm → 21 cm is about 1.36×, and 15 cm → 21 cm is 1.96×, nearly double.
When moving between loaf, chiffon, muffin, or sheet pans and other pans, thickness doesn’t match, so the ratio uses the amount of batter poured into each pan’s volume (70% for round, square, and loaf pans, 80% for chiffon pans, 75% for muffin pans, and up to the entered thickness for sheet pans).
Loaf, chiffon, and muffin pans have sloped sides, so their volume is calculated as a frustum of a pyramid or cone from the top and bottom dimensions. Between pans of the same type, the effect of the slope nearly cancels out.
Chiffon pan height is calculated as a guide proportional to the diameter (17 cm = 8 cm, 20 cm = 9.5 cm), so 17 cm → 20 cm is about 1.68× and 17 cm → 23 cm about 2.6×. If your pan’s height differs, enter it again.
In recipe conversion, g and mL are rounded to one decimal place under 10 and to whole numbers above that, and tablespoons and teaspoons are converted in 1/4 increments into combinations like “2 tbsp and 1/2 tsp”. Eggs get grams added based on the net weight of a medium egg (whole 50 g, yolk 20 g, white 30 g).
Temperatures, times, cm, size numbers, and %, as well as instruction lines starting with “1.” or “①”, are left as they are without applying the ratio.
Baking time guidance reflects general tendencies in home ovens. It varies by oven model and batter, so finally check with a skewer.
All calculations and recipe rewriting happen in the browser, and pasted recipes are not sent to a server.

Questions this tool answers

Use Cake Pan Size Converter | Recipe Amounts When Changing Pans, like 15 cm → 18 cm for searches like these:

I want to make a 15 cm cake recipe in an 18 cm pan
I want to reduce an 18 cm recipe to 15 cm or 12 cm
I want to know the amounts for making a round-pan recipe in a square pan
I want to make a loaf-pan recipe in a round or muffin pan
I want to scale a 17 cm chiffon cake recipe to 20 cm
I want to know the amounts when changing a roll cake sheet pan size
I want to know a cake size’s diameter and number of servings
I want to know how many eggs an 18 cm sponge cake needs
I want to know the grams for a fractional number of eggs
I want to multiply a recipe’s ingredients by 1.5× or 2× all at once

FAQ

How much should I multiply a 15 cm recipe to make it in an 18 cm pan?: 1.44×. For round pans, base area changes with the square of the diameter ratio, so (18 ÷ 15)² = 1.44. A 2-egg recipe becomes 2.88 eggs, so about 3 eggs (or 144 g of beaten egg). Conversely, making an 18 cm recipe in a 15 cm pan takes about 0.69×.
How do Japanese cake sizes relate to diameter and servings?: Size 1 = 3 cm in diameter, so as a guide size 4 = 12 cm (2–4 people), size 5 = 15 cm (4–6), size 6 = 18 cm (6–8), size 7 = 21 cm (8–10), and size 8 = 24 cm (10–12). In the “Size & ratio chart” tab you can also check recipe ratios based on size 5 and egg counts for sponge cakes.
How do I convert a round-pan recipe to a square pan?: To bake at the same thickness, convert by the ratio of base areas. Making an 18 cm round-pan recipe (about 254 cm²) in an 18 cm square pan (324 cm²) is about 1.27×, and in a 15 cm square pan about 0.88×. An 18 cm round pan has about the same area as a 16 cm square pan.
Can I make a loaf-pan recipe in a round or muffin pan?: Yes. Since the pans differ in thickness, convert by batter amount (volume). A recipe for an 18 × 8 cm loaf pan is about 1.4× for a 15 cm round pan, or about 8 standard muffins (7 cm top diameter). Moving to muffin or small pans shortens the baking time.
How do I make a 17 cm chiffon cake recipe in a 20 cm pan?: About 1.68× is a guide. A chiffon pan’s height changes with its diameter, so it’s the ratio of volumes (nearly the cube of the diameter ratio). A recipe with 3 yolks and 4 whites becomes about 5 yolks and 6–7 whites. For a 23 cm pan it’s about 2.6×.
The calculation gives a fractional number of eggs like 2.9. What should I do?: Weighing beaten egg is the reliable way. A medium egg is about 50 g net (yolk 20 g, white 30 g), so for 2.9 eggs use 145 g of beaten egg. For batters where whipping eggs matters, like sponge or chiffon, you can round the eggs up and increase the other ingredients accordingly.
How much longer should I bake when using a bigger pan?: As a guide, keep the temperature the same as the original recipe or lower it by 10°C, and extend the baking time by 5–15 minutes. For a smaller pan, shorten it by 5–10 minutes. The thicker the batter, the harder it is for the center to cook, so cover with foil if the top starts to burn, and bake until a skewer comes out clean.
How are tablespoons and teaspoons converted?: It converts to teaspoons with 1 tbsp = 3 tsp, rounds to 1/4 increments, and then shows combinations like “2 tbsp and 1/2 tsp”. Amounts under 1/4 spoon are hard to measure, so adjust things like vanilla oil and salt to taste.

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