The one formula you need
Ingredient weight = flour weight × baker's percentage ÷ 100. That is the entire system. Percentages are always computed against the flour — never against the total dough weight, which is why a formula's percentages sum to well over 100%. A lean sourdough at 100% flour, 70% water, 20% starter and 2% salt totals 192%, meaning the finished dough weighs 192% of the flour weight: 500 g of flour gives 960 g of dough.
A worked example: scaling a sourdough
| Ingredient | Baker's % | For 500 g flour | For 1,000 g flour |
|---|---|---|---|
| Bread flour | 100% | 500 g | 1,000 g |
| Water | 70% | 350 g | 700 g |
| Starter (100% hydration) | 20% | 100 g | 200 g |
| Salt | 2% | 10 g | 20 g |
| Total dough | 192% | 960 g | 1,920 g |
Scaling is where the system earns its keep. Want two loaves instead of one? Double the flour to 1,000 g and every other weight doubles with it — no re-reading the recipe, no rounding errors creeping in from cup conversions. Want a single small loaf? Use 300 g of flour: 210 g water, 60 g starter, 6 g salt.
Reading a formula at a glance
Once you know the ranges, a formula reads like a weather report. Hydration below 60% is a stiff dough — bagels, pretzels, pasta. Between 65% and 75% is the everyday bread zone: sandwich loaves, sourdough, pizza dough. Above 80% is wet and slack: ciabatta, focaccia, high-hydration sourdough with an open, holey crumb. Salt almost always sits at 1.8–2.2%: below that bread tastes flat, above it fermentation slows and the crumb tightens. Yeast in commercial formulas runs 0.5–2% depending on speed; sourdough starter typically 10–30% of flour weight, with more starter meaning a faster, tangier ferment.
The starter question, answered honestly
Purists include the starter's flour and water in the totals: a 100 g starter at 100% hydration contributes 50 g flour and 50 g water, so "true" hydration of the example above is (350 + 50) ÷ (500 + 50) = 72.7%, not 70%. Many home recipes ignore this and quote percentages against the main flour only. Neither is wrong as long as you know which convention a recipe uses — but when a dough feels wetter than its stated hydration, the starter is usually the reason. Our sourdough hydration calculator shows both figures so there is no ambiguity.
For the weights behind the percentages, see the cups to grams cheat sheet and the yeast conversion chart, or browse all guides from the homepage.