FreeToolStation

Serving Size Calculator: Scale a Recipe Up or Down

Every ingredient rescaled for the number you are feeding.

Home & Energy Calculators Free, no sign-up Runs in your browser

Amount, unit, name. The unit is optional.

—
Scale factor
—
Servings
—
Ingredients
—
Direction
—
Tin size change
IngredientOriginalScaled
Quantities scale; cooking does not. Baking times change far less than the amounts do, tin depth matters more than tin area, and strong flavours -- salt, chilli, spices, raising agents -- are usually better scaled by slightly less than the factor and adjusted by taste.

About the Serving Size Calculator

Serving Size Calculator rescales a whole ingredient list at once. Paste the ingredients with the amount at the start of each line, say what the recipe serves and what you need, and every quantity comes back multiplied. Fractions are understood, because recipes are full of them, and lines with no number -- a pinch of salt, a splash of oil -- are passed through untouched rather than mangled.

The results are rounded to amounts a kitchen can actually measure. Scaling 2 eggs by 1.5 gives 3, and scaling 175 grams by 1.5 gives 263 rather than 262.5, because no domestic scale shows half a gram. Smaller quantities are rounded to quarters and eighths, which is what measuring spoons come in.

What the arithmetic cannot do is cook. Baking time barely moves when a recipe doubles, because the limiting factor is how fast heat reaches the middle, and a tin's width should go up by the square root of the factor rather than the factor itself -- doubling a recipe needs a tin about 1.4 times wider, not twice. Salt, spices and raising agents are usually better scaled slightly under and adjusted by taste.

The page shows its working, not just its answer. Where there is a formula it is printed with your own numbers substituted in, so you can check the result rather than take it on trust -- which is the difference between a calculator you can use for something that matters and one you cannot.

Everything runs inside your browser. What you type is never uploaded, never logged and never stored, and the calculator keeps working if your connection drops after the page has loaded.

How to use the Serving Size Calculator

  1. Enter recipe serves, you want to serve and ingredients, one per lineDecimals are fine, and thousands separators are accepted and ignored.
  2. Read the scale factor, servings and ingredientsThe figures update as you type. The Calculate button is there if you would rather press something, but nothing waits for it.
  3. Copy or check the resultCopy the summary with the copy button, or open the table to check it row by row. The download button saves it as a file.

Features

  • Shows scale factor, servings, ingredients, direction and tin size change together, so you are not running it twice
  • A results table you can read across
  • Updates as you type, with no button to press and no page reload
  • Copy the result in one click
  • Download the detail as a .csv for a spreadsheet
  • Free, no sign-up, and it runs entirely in your browser

Who uses this tool

The serving size calculator is used by writers, developers, students, marketers and anyone else who needs the job done once without installing software. Common cases include:

  • Doubling a recipe for twice the guests
  • Halving a recipe written for a family
  • Scaling a bake to the tin you actually own
  • Working out a shopping list for a larger batch

Frequently asked questions

How do I enter each ingredient?

Put the amount first: "400 g plain flour". The unit is optional, and fractions like 1/2 or 1 1/4 are understood.

Does the cooking time scale too?

No, and this does not change it. Baking time moves far less than quantity does, because what limits it is heat reaching the middle.

What tin should I use for a doubled recipe?

One about 1.4 times wider, not twice. Area scales with the square of the width, so the width goes as the square root of the factor.

Why are some amounts rounded oddly?

They are rounded to something you can measure: whole units for large amounts, quarters and eighths for small ones.

If the serving size calculator is not quite what you need, these other free tools solve closely related problems, and there are 17 more in home & energy calculators.

Volume Converter

Convert volume between metric, US and imperial units.

Unit Converters Use tool

Weight Converter

Convert weight between metric and imperial units.

Unit Converters Use tool

Checked and rebuilt on 2026-10-14. The method this calculator uses is described in the section above, and corrections go through the contact page.