How these numbers are sourced
Where every formula and figure on BakeryMath comes from, how confident we are in it, and where honest uncertainty remains. Each calculator page also lists its sources under the tool, and the guides go through the methods step by step.
Baker's percentagehigh
Every ingredient's weight is expressed as a percentage of the total flour weight (flour is always defined as 100%, so the percentages add up to well over 100%). This is the standard notation used in professional bakeries worldwide specifically because you can change any one ingredient without re-figuring every other percentage. Sourced from King Arthur Baking's professional baker's-percentage reference and the Wikipedia "Baker percentage" article, which give the same definition — no disagreement found between sources.
Large-batch yeast adjustmentmedium
Yeast doesn't need to scale in a straight line with everything else: yeast multiplies inside the dough as it ferments, so a large batch needs proportionally less added yeast than a small one to reach the same proof, and over-yeasting a big batch causes over-proofing and a coarse, off-tasting crumb. Sourcing guidance varies in the specifics rather than agreeing on one number: some baking references suggest keeping yeast at a full linear scale up to about 3x a recipe and cutting it to roughly 90% of the linear amount above that; others suggest a more aggressive cut even at 2x (around 75% of linear, i.e. 1.5x the yeast for a doubled recipe rather than 2x). BakeryMath shows the plain linear amount and a suggested adjusted range side by side rather than picking one figure and presenting it as exact — treat the adjusted number as a starting point to taste/texture-test, not a guarantee.
Salt in large batches (adjustment removed)high
Earlier versions of the Batch Scaling Calculator suggested scaling salt to about 85% of the linear amount in big batches, based on a rule of thumb repeated in cooking-scaling guides. We could not trace it to any reliable bread source, while professional bread formulas keep salt at the same baker's percentage (often around 2% of the flour, as in King Arthur Baking's white bread example) at every batch size. The salt suggestion was removed on 2026-10-25; salt is now always scaled linearly.
Recipe costing & cost per portionhigh
Straightforward unit economics, not an industry-specific formula: sum each ingredient's used-quantity cost (price paid ÷ quantity purchased × quantity used), divide the total by the number of portions. No external citation needed beyond basic arithmetic.
Menu / product pricing (food-cost-percentage method)high
The standard restaurant/bakery pricing method: Price = Ingredient Cost ÷ Target Food Cost %. A cost-per-portion of $4.00 at a 30% target food cost prices at $4.00 ÷ 0.30 = $13.33. Johnson & Wales University's guidance puts a profitable restaurant at an average food cost of 28-35% and uses a 30% ideal food cost in its own example (until 2026-10-25 this page said 25-35%, a range we could not match to that source). No disagreement found on the method; the exact "ideal" percentage is inherently business-specific, which is why it's offered as an adjustable target rather than a fixed number.