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Recipe Scaler

Doubling a recipe is easy until the amounts stop being whole. Three quarters of a cup becomes nine eighths, and the usual approach — rounding each line as you go — quietly changes the recipe, because the ratios between the ingredients no longer hold. Here the scaling stays exact and only the printed amount is rounded, so the proportions survive even where the numbers get awkward.

What this generator does

Reads the amount, unit and ingredient from each line, multiplies every amount by the same factor, and prints each one rounded to something you can actually measure; an amount too small for that prints as 'under 1/8' of its unit, or to a tenth of a gram or millilitre, never as 0.

How to use this tool

  1. Paste the ingredients, one per line, with the amounts as they are written.
  2. Say how many the recipe serves and how many you need.
  3. Read the scaled list, or use the halve and double buttons.
  4. Lines without an amount — a pinch, to taste — are left exactly as they were.

Understanding the controls

Ingredients
One per line. Amounts may be whole numbers, decimals, fractions like 1/2, mixed numbers like 1 1/2, or the single characters ½ and ¾.
Written for and you want
The servings the recipe is written for and the number you need. The factor is simply one divided by the other, shown so you can see it.

Worked examples

Written for 4, scaling to 6 (a factor of 1.5)
3/4 cup flour becomes 9/8 of a cup, printed as "1 1/8 cup flour" to the nearest eighth — the unit is left as you typed it. 2 eggs becomes 3 eggs. The same 1.5x factor applied to both is what keeps the flour-to-eggs ratio exactly as it was, even though one line rounds cleanly and the other does not.

Common use cases

  • Cooking for six from a recipe written for four
  • Halving a cake recipe for a smaller tin
  • Scaling a recipe up for a party without losing the balance
  • Working out a shopping list for a batch cook
  • Converting a family recipe to a different number of portions

How this generator works

The exact scaled amount is kept alongside the printed one, and the checks look at the exact figures rather than the text — checking the printed amounts would be checking the rounding rather than the scaling. It is confirmed that every amount moved by exactly the same factor, that every pair of ingredients holds the same ratio to each other as it did before, that every line is still there in its place, and that the factor is the one the servings ask for.

Randomness and fairness

Nothing is random. The same ingredients and servings always give the same result.

For how randomness is produced across the whole site, see how Generate Random works.

Limitations and good to know

  • Amounts are rounded to whole numbers for grams, millilitres and anything of ten or more, and to eighths otherwise, so a scaled recipe is not exact on the page even though the arithmetic behind it is.
  • Units are not converted: grams stay grams and cups stay cups.
  • Cooking times, tin sizes and oven temperatures do not scale with the ingredients, and none of them is adjusted here.
  • An ingredient written without a number is left alone, which is usually right for a pinch and wrong for an egg.

Privacy and your data

Your recipe stays in your browser. Nothing you paste is transmitted or stored.

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