Sourdough Hydration Calculator
Built by Johnny Alto · free, no sign-up · updated July 26, 2026
Enter your flour, water, and starter to see your dough's true hydration. The number most recipes quote ignores the flour and water hiding inside the starter, so this calculator folds those in to give the overall hydration that actually shapes your crumb.
Overall hydration0%includes starter
Total flour0grams
Total dough0grams
Hydration is total water divided by total flour. A 100 percent starter is half flour, half water by weight. Most home loaves live between 65 and 75 percent; higher hydration gives a more open crumb but a stickier, harder-to-handle dough.
What sourdough hydration really means
Hydration is the weight of water divided by the weight of flour, written as a percentage. The catch with sourdough is the starter: it is itself made of flour and water, and leaving it out of the math makes your dough look drier than it is. A starter kept at 100 percent hydration is equal parts flour and water by weight, so 100 grams of it adds 50 grams of flour and 50 grams of water to the recipe.
This calculator splits the starter into its flour and water, adds them to what you pour in directly, and reports the overall hydration. That is the figure that governs how open the crumb is and how the dough handles.
Choosing a hydration level
Most home bakers work between 65 and 75 percent. Lower hydration doughs are firmer and easier to shape, which suits beginners and sandwich loaves. Higher hydration gives the open, airy crumb people chase in an artisan loaf, but the dough is slack and sticky and takes practice to handle. Change one variable at a time and keep notes, since flour type and even humidity shift how a given hydration behaves.
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Frequently asked questions
How do I calculate sourdough hydration?
Divide the total water by the total flour and multiply by 100. Remember to count the flour and water inside your starter, which a 100 percent starter splits evenly by weight.
Does the starter count toward hydration?
Yes. A starter is flour and water, so it changes the overall hydration. A 100 percent starter adds equal weights of flour and water, which this calculator folds in for you.
What hydration should sourdough be?
Most home loaves are 65 to 75 percent. Lower is firmer and easier to handle; higher gives a more open crumb but a stickier dough.
Why is my dough so sticky?
High hydration doughs are naturally slack and sticky. If it is unmanageable, lower the water a few percent, use wet hands instead of flour when shaping, and build strength with stretch and folds.
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This calculator gives estimates for planning only; always confirm against your own measurements and species research. Some links are to our buying guides, which contain affiliate links. As an Amazon Associate I earn from qualifying purchases.
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