Recipe Scaler

Paste an ingredient list and rescale every quantity to the servings you want — fractions stay fractions.

How to use

  1. Paste the ingredient list, one per line, exactly as it appears in the recipe.
  2. Set what the recipe yields and how many servings you want — or use the ½×, 2× and 3× buttons.
  3. Copy or download the rescaled list. Lines with no number, like "salt to taste", are left untouched.

About this tool

Scaling a recipe by hand is where good cooking goes wrong: it is easy to double the flour and forget the salt, and multiplying 3/4 by 3 in your head rarely ends in a usable measurement. This tool reads the list you paste line by line and looks for a quantity at the start of each one. It understands whole numbers, decimals written with a comma or a dot, fractions like 3/4, mixed numbers like 1 1/2, the typographic fractions ½ and ¾, thousands separators such as 1.500 g, ranges like "2 to 3 tablespoons", and bullet or numbered list markers, which are preserved. Everything after the number — the unit, the ingredient, the note in parentheses — is copied through untouched.

The arithmetic is done with exact fractions rather than decimals, which is what makes the output usable in a kitchen. The scaling factor itself is a fraction (8 servings from a recipe for 4 is exactly 2, 2 servings from 6 is exactly 1/3), and each quantity is multiplied as a fraction and then reduced. So 1/2 teaspoon tripled becomes 1 1/2 teaspoons, not 1.5; 3/4 cup doubled becomes 1 1/2 cups; 2 cups times 1.5 becomes a clean 3. Quantities originally written as decimals stay decimals, whole numbers become fractions only when the result lands on a simple denominator, and no floating-point noise like 0.30000000000000004 ever reaches the screen.

Two honest limits. Ingredients scale linearly, but cooking does not: pan size, baking time, oven behaviour, leavening and salt often need judgement rather than multiplication, and halving a recipe with three eggs leaves you with 1 1/2 eggs to resolve by hand (beat one and use half). The tool also does not rewrite the text, so "1 cups" may appear when a plural stops making sense — fixing grammar in every language would risk mangling the ingredient itself. Nothing you paste is uploaded: the parser and the arithmetic run entirely in your browser.

Frequently asked questions

How do I double a recipe?

Paste the ingredients and click the 2× button — the desired servings field is filled automatically and every quantity is doubled. The ½× and 3× buttons work the same way, and any other ratio can be typed directly into the two serving fields.

Are fractions kept as fractions?

Yes. Quantities are multiplied as exact fractions and written back as fractions whenever possible, so 1/2 tripled shows as 1 1/2 and 3/4 doubled shows as 1 1/2. Decimal quantities stay decimal, and results that are not a simple fraction fall back to a decimal number.

What happens to lines like "salt to taste"?

They pass through unchanged. Only a number at the start of the line is rescaled, so headings such as "Filling:", instructions and open-ended amounts survive untouched — which is why you can paste a whole ingredient block without cleaning it up first.

Does doubling a cake recipe always work?

The ingredients scale, the physics do not. Baking time, pan size and leavening rarely double along with the quantities, and strong seasonings such as salt, spices and chilli are usually better increased by taste. Treat the output as the arithmetic done right, not as a rewritten recipe.

Does my recipe leave my browser?

No. The list is parsed and rescaled locally in JavaScript on your device — nothing is sent to a server, stored or logged, and the download is generated in the page itself.

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