Sourdough hydration calculator
Calculate overall hydration including your starter, or find the separate water needed for a target hydration.
Starter is treated as flour and water only. Water in eggs, dairy and other ingredients is not inferred. Negative required added water is rejected. Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.
Your result
How to use Sourdough hydration calculator
- Enter the measurements and assumptions for this recipe or plan.
- Review the calculated quantities and their stated basis.
- Download the report and verify it against your measured result.
Useful next steps
Count the starter contributions
A 100 g starter at 100% hydration contains 50 g flour and 50 g water. Added to 500 g flour and 300 g water, the overall dough is about 63.64% hydration.
Solve for the next mix
Switch to Reach target hydration to calculate added water while holding flour and starter fixed. At 70% in the example, add 335 g water outside the starter.
Save the result
Download CSV and a text or JSON report with the calculation and its assumptions. Processing stays on your device. Check measurements and selected units before using the result.