Sourdough Hydration Calculator
Flour, water and starter in grams — get your dough's true hydration, counting the water and flour hiding inside your starter.
Most starters are kept at 100% hydration (fed equal weights flour and water). If yours is stiffer (e.g. 50%), the true hydration is slightly lower than calculated.
How the math works
total water = water + starter × 0.5
hydration % = total water ÷ total flour × 100
Baker's percentages always compare water to flour, not to total dough weight. The step most bakers miss is the starter: a 100% hydration starter is exactly half water by weight, so every 100 g of starter quietly brings 50 g of flour and 50 g of water into your dough. That's why a recipe calling for 500 g flour, 350 g water and 100 g starter is really a 75% hydration dough, not the 70% the plain numbers suggest.
What hydration means for your loaf
Around 68–70% is a beginner-friendly range — dough that's easy to shape and holds structure. 72–78% gives larger, more irregular holes and a thinner, crisper crust, but the dough is stickier and rewards good folding technique. Above 80% you're in high-hybrid territory (ciabatta-style) that needs wet hands and confidence.
FAQ
- My starter is 50% hydration — can I still use this?
- The result will read slightly high. As a rule of thumb, a stiff starter lowers true hydration by roughly 1–2 percentage points at typical 20% starter amounts.
- Does salt affect hydration?
- Salt is counted in baker's percentages separately (usually 2%) and doesn't change the hydration number. We include it only so the total dough weight is right.
- Should I adjust hydration for new flour?
- Whole grain flours absorb more water. When switching to whole wheat, expect to add 1–3 percentage points of water for the same feel.