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Sourdough Hydration Calculator
Enter the flour you weigh out and the starter you plan to use. Hydration is measured against total flour, starter included.
Hydration excludes the water used to dissolve salt or wet your hands. Add that separately if you track it.
The arithmetic
Starter flour = starter ÷ (1 + starter hydration). Total flour = added flour + starter flour. Total water = total flour × target hydration. Water to add = total water − starter water.
What changes the dough beyond hydration
Flour type, fermentation temperature and shaping technique matter as much as the percentage. A 75% dough made with strong bread flour behaves very differently from the same number with whole wheat.
Frequently asked questions
Can the water to add be negative?
Only with an unusually wet starter and a low target hydration. It means the starter already carries more water than the recipe needs; do not pour any away without adjusting the flour.
Does the salt percentage include starter flour?
Yes. It is applied to total flour, matching how the hydration is calculated.
Is this for levain or discard?
Any starter works if you enter its true hydration. Discard is usually the same hydration as the starter it came from.