Scale a bread formula
Baker's percentages make a recipe scale to any flour weight — 65 % water stays 65 % at 500 g or 5 kg.
Tools used in this guide
The job
Professional bread formulas are written as percentages of flour weight, so they scale cleanly. Water percent is 'hydration': 60 % is a firm sandwich dough, 75–80 % is airy ciabatta territory, above that is expert-level slack.
Flour and percentages
Enter the flour weight you want to use, then water, salt, and yeast as percentages of it — plus an optional levain percent and its hydration, which the tool counts back into the flour and water. A typical starting point: 100 % flour, 65 % water, 2 % salt, 1 % instant yeast.
Worked example
500 g flour at 65/2/1 with levain left at 0: 325 g water, 10 g salt, 5 g yeast — 840 g of dough. With the default 20 % levain (100 % hydration) the same flour reads 940 g total and ~68 % effective hydration, because the levain's own flour and water count in.
Where it stops
Sourdough starter is flour+water — a 20 % starter at 100 % hydration adds its halves to both flour and water percentages. Whole-grain flour drinks more water than white; hydration that's right for one is soupy in the other.