Hydration check
How to read added hydration and total hydration
Sourdough hydration can be confusing because a starter or levain already contains flour and water. This calculator separates the measured starter into its internal flour and water, then adds those amounts to the main formula totals. That gives you a total hydration number that reflects the whole dough, not only the water poured into the bowl.
Use the Add to bowl section for weighing: main flour, added water, starter, and salt. Use the Starter split and Formula totals sections for interpretation. The split is not an extra ingredient list; it is the accounting that explains why the total hydration can differ from the simple added-water percentage.
This is useful when comparing recipes that report hydration differently. Some recipes mean added water divided by main flour. Others include levain flour and levain water. DoughMath shows both concepts where possible so you can adjust water without accidentally double-counting the starter.
Use this section for
- • Starter is measured once but split for formula math.
- • Total hydration includes starter flour and water.
- • Salt percentage is checked against total flour.
Example
Example calculation
These are illustrative inputs for the calculator on this page. Change the fields above to make the result match your own dough.
100g of 100% hydration starter
Input: Main flour 500g, added water 350g, starter 100g, salt 10g.
Output: Starter flour 50g, starter water 50g, total hydration 72.7%, salt 1.8%.
Formula
How this calculator works
- Starter flour = starter weight ÷ (1 + starter hydration ÷ 100).
- Starter water = starter weight − starter flour.
- Total hydration = total water ÷ total flour × 100.
- Salt percentage is calculated against total flour, including starter flour.
Common mistakes
What to check before baking
- Do not calculate salt percentage from main flour only if you want total formula salt percentage.
- Do not add starter flour and water again to the bowl. The starter itself is the measured ingredient.
- Do not mix cups and grams in the same formula unless you have weighed the cup measurements first.
- Do not treat a 100% hydration starter as 100% water. It is equal parts flour and water by weight.
FAQ
Questions
Does starter count toward hydration?
In this calculator, yes. The starter is split into internal flour and water before total hydration is calculated.
Is 100g of 100% hydration starter 100g of water?
No. It is about 50g flour and 50g water.
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