Sourdough Hydration Calculator
Real baker's math, starter included. Check the hydration of a recipe you're following, find exactly how much water to add for a target percentage, or scale a complete sourdough recipe from a dough weight — with flour, water, starter and salt in grams.
Total dough hydration
72.7%
Medium-high hydration — classic artisan sourdough range
Total flour
550 g
Total water
400 g
Flour from starter
50 g
Water from starter
50 g
What hydration actually means
Hydration is the weight of water in a dough expressed as a percentage of the weight of flour — the core of baker's percentages, where flour is always 100%. A dough with 500 g flour and 350 g water is at 350 ÷ 500 × 100 = 70% hydration. Water is the main lever for crumb texture: more water means a more open, irregular crumb and a thinner, crisper crust, but also a stickier, harder-to-shape dough.
The percentage only tells the whole truth when it includes the flour and water hiding inside your starter — which is where most hand calculations go wrong.
How the starter changes the math
A starter at 100% hydration is half flour, half water by weight. In general, for a starter kept at sh% hydration:
starterWater = starter − starterFlour
hydration % = (water + starterWater) ÷ (flour + starterFlour) × 100
Worked example: 500 g flour, 350 g water, 100 g starter at 100% hydration. The starter contributes 50 g flour and 50 g water, so total flour is 550 g and total water is 400 g. True hydration = 400 ÷ 550 × 100 = 72.7% — not the 70% you'd get by ignoring the starter. On stiffer starters (say 50% hydration) the gap grows, because the starter brings proportionally more flour.
Typical hydration ranges
| Bread style | Hydration | Dough feel |
|---|---|---|
| Bagels, pretzels | 55–65% | Stiff, dense, easy to shape |
| Sandwich loaves | 60–68% | Soft but manageable |
| Artisan sourdough boules | 70–75% | Tacky, needs folds not kneading |
| Ciabatta, focaccia | 75–85%+ | Slack, wet, advanced handling |
Handling changes with the level: below ~68% you can knead on the counter; at 70–75% switch to stretch-and-folds in the bowl with wet hands; above 78% coil folds and a well-floured bench become essential, and baking in a pan (focaccia-style) is often the saner choice.
More kitchen math
Converting a recipe from cups to weight first? The grams to cups converter handles flour and water by volume, the recipe converter scales whole ingredient lists up or down, and the cooking measurement converter covers everything from tablespoons to milliliters.