Free Ingredient Scaling calculator with clear step-by-step results.
Not every ingredient scales at the same rate. Bulk ingredients scale linearly with servings, but salt, spice and chemical leavening scale sub-linearly because perceived intensity and reaction rates do not follow volume - a common cause of over-seasoned large batches.
Serving factor
Factor = target servings / original servings
Sub-linear scaling
Applied factor = serving factor raised to the power 0.75
Perceived saltiness follows a compressive response to concentration, and a bigger batch also has proportionally less surface area losing seasoning. Scaling salt linearly usually tastes too salty.
Also sub-linear. Doubling a cake recipe with double the leavening frequently produces a coarse crumb that collapses; roughly 1.7 times is a better starting point.