Baker's math, made human
Sourdough Hydration Calculator
Find the true hydration of any dough - including the flour and water hidden inside your starter - plus baker's percentages and exact water tweaks for the texture you want.
Your dough
Enter your recipe in grams; the calculator includes the flour and water hidden inside your starter, so the result is your true hydration.
True hydration (incl. starter)
70%
Medium hydration
Total flour
500 g
Total water
350 g
Dough weight
860 g
Salt (baker's %)
2.0%
| Ingredient | Grams | % of flour |
|---|---|---|
| Added flour | 500 g | 100% |
| Added water | 350 g | 70% |
| Starter | 0 g | 0% |
| Salt | 10 g | 2% |
Add 25 g of water to reach 75%.
What is sourdough hydration?
Hydration is the water-to-flour ratio of your dough, written as a percentage. A 70% dough contains 70 g of water for every 100 g of flour. It is the single most important number in a sourdough recipe: it decides whether you get a tight sandwich crumb or an open, airy, holey loaf, and how sticky, slack, and hard to shape the dough will be.
Most home-baker calculators stop at the water you add. But your starter is itself ~50% water and ~50% flour (at 100% hydration), so a recipe with 500 g flour, 350 g water, and 100 g of starter is actually 72.7% hydrated, not 70%. This calculator does the starter math for you.
Hydration levels at a glance
What each hydration range means for 500 g of flour (water shown per 100 g of flour).
| Level | Hydration | Water / 100 g flour | Feels like | |||
|---|---|---|---|---|---|---|
| Low hydration | 0–65% | 0–65 g | Stiff, easy-to-handle dough with a tight crumb. Great for beginners and shaped loaves like bagels. | Stiff, easy-to-handle dough with a tight crumb. Great for beginners and shaped loaves like bagels. | ||
| Medium hydration | 66–74% | 66–74 g | The classic sandwich-loaf range. Manageable by hand, open enough crumb for everyday bread. | The classic sandwich-loaf range. Manageable by hand, open enough crumb for everyday bread. | ||
| High hydration | 75–82% | 75–82 g | Slack, sticky dough with an open, airy crumb. Expect coil folds and a bench scraper. | Slack, sticky dough with an open, airy crumb. Expect coil folds and a bench scraper. | ||
| Very high hydration | 83–100+% | 83–100+ g | Focaccia territory. Almost batter-like; shaping is done in the pan or with heavy flouring. | Focaccia territory. Almost batter-like; shaping is done in the pan or with heavy flouring. | ||
More baking tools
Starter Feeding Calculator
Feed ratios (1:1:1 → 1:10:10) and exact flour/water for any amount of starter.
Recipe Scaler
Scale any formula to more loaves or a target dough weight.
Baker's Percentage Calculator
Percentages → gram amounts, the professional way.
Pizza Dough Calculator
Balls, hydration, salt, from Neapolitan to pan style.
Quick answers
Why is my dough 72% hydrated when the recipe says 70%?
Because your starter contributes flour and water. With 500 g flour, 350 g water and 100 g of 100%-hydrated starter you get 550 g total flour and 400 g total water, that's 72.7%.
What hydration should a beginner use?
Start around 65–70%. The dough is stiffer, easier to shape, and far more forgiving while you learn folds and fermentation.
What does "100% hydration starter" mean?
The starter was fed equal parts flour and water by weight. A 100 g sample is therefore ~50 g flour and ~50 g water, which is why it matters in hydration math.