Do I double the tin size when I double the recipe?

Not the diameter. A 20cm tin doubled in capacity needs about 28cm, since area goes as the square of the diameter. Doubling to 40cm gives four times the capacity.

Does cooking time double?

No. Time depends mostly on depth. Doubling a recipe into a wider tin at the same depth barely changes it.

Conversionscooking

Recipe Scaling Calculator

Recipe quantities scaled with the right bakeware size. Ingredients scale linearly and tin diameter does not: it scales by the square root, because it is area that holds the mixture.

Also called: scale recipe calculator, halve a recipe.

Scaled quantities

625, 1250, 5, 3.75, 75

Multiply every ingredient by 2.5: 625, 1250, 5, 3.75, 75. Bakeware should go from 20cm to about 31.6cm, since area scales as the square. Salt, chilli and raising agents usually need less than the full multiple. Season up gradually and taste.

Multiply everything by

2.5

Suggested tin diameter

31.6

Tin area multiplies by

2.5

On seasoning and time

Salt, chilli and raising agents usually need less than the full multiple. Season up gradually and taste.

How this is calculated

Method and background

How this is calculated

Every ingredient multiplies by the ratio of servings. Bakeware is the part that goes wrong: doubling a recipe does not mean doubling the tin diameter, because a tin of twice the diameter holds four times as much. The diameter should grow by the square root of the factor instead. Salt, spice and leavening also do not scale linearly in practice, and cooking time changes with depth rather than with volume.

quantities scale linearly, but tin diameter scales by the square root because area is what holds the batter

k: Scale factor

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

four servings to ten

Original servings: 4
Desired servings: 10
Ingredient quantities: 250, 500, 2, 1.5, 30
Original tin diameter: 20 cm

Scaled quantities625, 1250, 5, 3.75, 75

20 x root 2.5

Open this example

the same servings changes nothing

Original servings: 4
Desired servings: 4
Ingredient quantities: 250, 500
Original tin diameter: 20 cm

Scaled quantities250, 500

boundary

Open this example

Method and limits

What it assumes

Uniform depth in the scaled tin.

What it deliberately does not model

Salt, chilli and raising agents usually need scaling by less than the full factor.
Cooking time changes with the depth of the dish, not with the quantity.

Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator

Frequently asked questions

Do I double the tin size when I double the recipe?: Not the diameter. A 20cm tin doubled in capacity needs about 28cm, since area goes as the square of the diameter. Doubling to 40cm gives four times the capacity.
Does cooking time double?: No. Time depends mostly on depth. Doubling a recipe into a wider tin at the same depth barely changes it.