Recipe scaling uses a single multiplier called the scale factor. Divide your desired servings by the original servings and you have it: original 4 servings, desired 10 servings, scale factor is 2.5. Multiply every ingredient amount by 2.5 and you have an exact scaled recipe. This calculator runs all your ingredients through that multiplication simultaneously so you do not need to do it one by one.
The scaled amounts stay in the same units as the original: a 2-cup flour at 2.5x becomes 5 cups, not a conversion to tablespoons or grams. You can change units manually afterward using the common conversions reference in the sidebar. Fractions are handled automatically: 0.75 cup is returned as-is, and you can cross-reference that 0.75 cup equals 12 tablespoons if you need a simpler measurement.
Once you have scaled quantities, use our recipe cost calculator to see how total ingredient cost and cost per serving change at the new batch size. Scaling up reduces cost per serving when buying in bulk, while scaling down often increases it.
Most ingredients scale perfectly linearly: flour, butter, eggs, milk, water, sugar. Double the recipe and these double. The exceptions are leavening agents, salt, and strong spices. Baking powder and baking soda at full mathematical scale in a large batch create a soapy, metallic taste and can cause baked goods to collapse. The standard adjustment is to scale leavening at about 75-80% of the mathematical result for batches above 3x.
Salt and strong spices like cayenne, cinnamon, and cloves follow a similar principle: the mathematical result is often too intense at large scale, so reduce them to 75-90% and adjust to taste. Yeast in bread dough is a special case, as the same small amount works across a wide range of batch sizes, from 1x up to 3x, because yeast multiplies during fermentation and is not bound by linear proportion the same way other leaveners are.
Pizza dough is a practical example where baker's percentage handles scaling more precisely than a simple multiplier. Our pizza dough calculatoruses baker's percentages to ensure exact hydration ratios regardless of batch size, which is more reliable than scaling a cup-based recipe with this tool.