What is dough hydration?
Hydration is the weight of water divided by the weight of flour, expressed as a percentage. A dough with 500 g flour and 350 g water is 70% hydration. Higher hydration (75–85%) gives an open, airy crumb but a stickier, harder-to-shape dough; lower (60–65%) is easier to handle and produces a tighter crumb.
The starter trap most calculators miss
Your starter contains both flour and water — and if it's not 100% hydration, counting the whole starter weight as "flour" (or as "water") skews the math. A 100 g starter at 80% hydration contains roughly 56 g flour and 44 g water. This calculator breaks the starter into its flour and water parts first, then computes the true total hydration — the step many popular tools get wrong.
How to use it
- Dough → Hydration: enter your flour, added water and starter. You get total hydration, the flour/water split inside the starter, and the baker's percentage of every ingredient.
- Target % → Water: set a target hydration and the calculator tells you exactly how much water to add, accounting for water already in the starter.
Baker's percentage reference
In baker's math, flour is always 100% and everything else is relative to it. A classic country loaf: 100% flour, 72% water, 20% starter, 2% salt. Keeping hydration and starter amounts consistent is what makes a recipe reproducible loaf after loaf.