Recipe Scaling Calculator

How This Calculator Works

Scaling a recipe means multiplying every ingredient’s quantity by the same factor — how many times bigger (or smaller) the new batch is than the original. Enter how many servings the recipe originally makes and how many you actually want, list out the ingredients, and this calculator multiplies each quantity by that ratio, so nothing needs figuring out by hand or gets missed.

Each ingredient keeps its own original unit (cups, tablespoons, grams, whatever the recipe uses) — only the number changes. Converting between units (like cups to grams) isn’t something this calculator does, since that depends on the specific ingredient’s density, which varies from one ingredient to the next.

The Formula

1. Scale factor: $\vD{\text{Scale Factor}} = \vA{\text{Desired Servings}} \div \vB{\text{Original Servings}}$
2. Each ingredient’s new quantity: $\text{New Quantity} = \vC{\text{Original Quantity}} \times \vD{\text{Scale Factor}}$

Worked Example

A recipe that makes 4 servings, scaled up to 6 servings:

1. Scale factor: $\vA{6} \div \vB{4} = \vD{1.5}$
2. 2 cups flour becomes $\vC{2} \times \vD{1.5} = 3$ cups.
3. 1 cup sugar becomes $\vC{1} \times \vD{1.5} = 1.5$ cups.
4. 3 eggs becomes $\vC{3} \times \vD{1.5} = 4.5$ — round to 4 or 5 eggs, since eggs don’t divide cleanly (whisking one egg and using about half is the usual workaround for a “half egg”).

Since this is a 1.5x scale-up, pan size and cook time are both worth double-checking — ingredient amounts scale evenly, but how long something takes to bake and what pan it fits in often don’t.