Recipe Scaler

Double, halve or resize a recipe to any serving count. Every quantity comes out in cooking-friendly fractions, and the ingredients that don’t scale linearly get flagged.

Your recipe

Servings

Quick scaleScale factor×1.5

Ingredients

Up to 40

Accepts 2, 2.5, ½, 1/2, 1½ and ranges like 2–3.

Paste a whole recipe

One ingredient per line, like “2 cups flour”. Lines without a number are kept as written.

Enter your servings and ingredients.

Your recipe stays on your device. Every calculation runs in your browser — nothing you type is uploaded or saved.

FAQ

Which ingredients should I not scale exactly?

Salt, spices, herbs and aromatics taste stronger as a batch grows: when doubling, start with about 1½ times the original seasoning instead of twice, then adjust to taste. Baking powder, baking soda and yeast also need less than the straight multiple — about 10–25% less when doubling or more, because extra leavening makes bakes rise fast and collapse. The scaler flags these rows so you know which numbers are a starting point rather than a final answer.

How do I measure a fraction of an egg?

Beat the egg in a small bowl, then measure what you need by weight or spoon — half a large egg is about 25 g or 1½ tablespoons. A yolk alone is a good stand-in for half an egg when the recipe needs binding. When a scaled amount lands under a quarter of an egg, rounding up to one yolk is usually close enough.

Why do results show 1½ instead of 1.5?

Measuring cups and spoons are marked in halves, thirds, quarters and eighths, so any result that lands within about 5% of one of those markings is shown as that fraction — 1½ cups is something you can actually measure. A result that doesn’t land near a standard marking falls back to a decimal instead.

Do cooking times scale with the servings?

No — time follows thickness and surface area, not quantity. A doubled casserole in a deeper dish may need 25–50% longer, and a doubled cake in the same pan usually fails entirely: change the pan size or bake two batches. Judge doneness with a thermometer or skewer rather than the clock.

What happens to a quantity like “2–3 cloves”?

Both ends of the range scale, so “2–3 cloves” in a recipe that doubles becomes “4–6 cloves”. The recipe writer’s intended flexibility is preserved instead of being averaged into a single number.

Written and reviewed by the BroBroGo editorial team.Last updated:

The Mathematics of Kitchen Fractions

Scaling a recipe involves more than multiplying numbers on a calculator. Standard kitchen measuring tools, such as cups and spoons, are marked in halves, thirds, quarters, and eighths. When a calculation yields a decimal value like 1.625, converting it into a practical measurement can be difficult during active cooking.

To resolve this, the Recipe Scaler uses a fraction rounding rule. Calculated quantities that fall within approximately 5% of a standard kitchen fraction are automatically displayed as fractions (such as 1½). This ensures the output matches physical measuring tools. If a calculated quantity does not fall near these standard markings, the tool defaults to displaying a decimal.

Non-Linear Scaling in Cooking

In culinary science, doubling every ingredient in a recipe by a strict linear multiplier can ruin the flavor profile of the dish. Certain ingredients, specifically seasonings, spices, herbs, aromatics, and salt, taste stronger as the total volume of a batch increases.

When doubling a recipe, scaling seasonings linearly often results in an overpowered dish. A reliable culinary rule of thumb is to start with 1½ times the original seasoning amount rather than twice the quantity. The Recipe Scaler flags these ingredients with specific warnings based on the direction of the scale:

  • Scaling Up: When increasing servings, the tool displays: "Seasonings don’t scale linearly — start a little under this and adjust to taste."
  • Scaling Down: When decreasing servings, the tool displays: "Seasonings don’t scale linearly — start with this, then adjust to taste."

The Chemistry of Leaveners

Leavening agents, including baking powder, baking soda, and yeast, do not scale in a linear fashion. In baked goods, these agents produce carbon dioxide gas to lift doughs and batters. If you scale up a recipe and double or triple the leaveners linearly, the excess gas causes the bake to rise too rapidly and subsequently collapse.

When scaling up a recipe, leavening agents require approximately 10–25% less than the straight linear multiple. Conversely, when scaling down, the full calculated amount is required to ensure the bake still rises. The tool applies the following contextual flags to guide bakers:

  • Scaling Up: "Leavening doesn’t scale linearly — use about 10–25% less than this."
  • Scaling Down: "Leavening doesn’t scale linearly — use the full amount shown."

Egg Math in Baking

Eggs serve as binders, leaveners, and moisture providers in baking, but they present a physical scaling challenge because they cannot be divided in the shell.

When a scaled recipe calls for a fraction of an egg, cooks can beat the egg in a small bowl and measure out the required portion by weight or volume. Half of a large egg is equivalent to approximately 25 g or 1½ tablespoons. If a recipe requires binding and calls for half an egg, a single yolk can serve as a suitable substitute. When the scaled calculation results in less than a quarter of an egg, rounding up to one yolk is generally sufficient.

The tool flags fractional egg results with the warning: "Eggs don’t divide in the shell — beat and measure, or round to whole eggs."

Heat Transfer vs. Volume

Cooking times and pan sizes do not scale proportionally with ingredient quantities. This is because heat transfer depends on the thickness and surface area of the food rather than its total weight.

If you double the ingredients of a casserole and place them into a deeper dish, the food will require roughly 25–50% longer to cook, not double the time. Doubling a cake recipe and baking it in the same pan size usually results in a baking failure. For successful results, you must either adjust the pan size or bake the batter in separate batches.

Because of these physical constraints, the tool displays a permanent cooking time note: "Cooking times don’t scale with servings — a doubled dish rarely needs double the time. Check doneness, not the clock."

Preserving Recipe Flexibility

Many recipes include ingredient ranges, such as "2–3 cloves of garlic", to allow for personal preference or natural variations in ingredient sizes. To preserve the original author's intent, the Recipe Scaler processes both ends of a range individually. For example, if you double a recipe containing "2–3" of an ingredient, the tool scales both numbers to output "4–6".

Additionally, when importing recipes, any line that does not contain a parsable number is preserved exactly as written and marked with the label "as written".

How the Scaler Processes Data

The Recipe Scaler performs all calculations locally. Every calculation runs entirely in the user's browser, meaning the recipe stays on the local device. Nothing typed into the tool is uploaded, saved, or sent to an external server.

The tool supports two input methods: individual structured rows or pasting bulk recipe text. It accepts quantities as whole numbers, decimals, fractions, mixed numbers, and ranges. The system enforces specific limits to ensure performance, such as a maximum serving count of 10,000 and a cap on the number of ingredient lines.

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