Ignoring starter water
The dough may be wetter than the calculation suggests because starter water was left out.
Sourdough calculator with starter
Sourdough Hydration Calculator Including Starter
Total hydration is not just added water divided by added flour. Your starter already contains flour and water, so a correct sourdough hydration calculation has to include both.
Use the formula below, then use The Baker when you want the app to handle starter contribution, scaling, and formula changes for you.
Hydration basics
What sourdough hydration means
Hydration is the total water in a dough expressed as a percentage of total flour. A 75% hydration dough contains 75g of water for every 100g of flour.
Basic formula
hydration % = total water / total flour * 100In yeasted bread this can be simple. In sourdough, the starter adds its own flour and water, so the total dough is larger than the flour and water you add directly to the bowl.
Starter contribution
Why starter contribution changes the result
A 100% hydration starter is half flour and half water by weight. If you add 200g of that starter, you are also adding 100g flour and 100g water.
That changes both sides of the hydration formula. Ignoring starter flour makes the dough look wetter than it really is, and ignoring starter water makes it look drier than it really is.
Worked example
Calculate hydration including a 100% hydration starter
Example dough: 900g added flour, 650g added water, and 200g starter at 100% hydration.
| Component | Flour | Water |
|---|---|---|
| Added dough ingredients | 900g | 650g |
| Starter contribution | 100g | 100g |
| Total formula | 1000g | 750g |
| Total hydration | 750 / 1000 * 100 = 75% | |
Common mistakes
Where sourdough hydration math goes wrong
Ignoring starter flour
The formula may appear too hydrated because the flour inside the starter was not counted.
Assuming every starter is 100%
A stiff starter and a liquid starter contribute different flour and water amounts.
How The Baker calculates it
Enter the starter and let the app include its flour and water
The Baker's hydration workflow is built for real sourdough formulas, where starter amount and starter hydration both matter.
- Counts flour and water contributed by the starter.
- Supports dough hydration calculations while you adjust formulas.
- Lets you try professional tools before upgrading to full Pro access.
Real hydration calculator screenshot
Related tools
Keep the rest of the formula consistent
FAQ
Sourdough hydration calculator FAQ
How do I calculate sourdough hydration including starter?
Add the flour and water from the starter to the flour and water added directly to the dough. Then divide total water by total flour and multiply by 100.
Does a 100% hydration starter mean equal flour and water?
Yes. A 100% hydration starter contains equal weights of flour and water, so 200g starter contributes 100g flour and 100g water.
Why is added water divided by added flour wrong for sourdough?
It ignores starter contribution. The starter changes both total flour and total water, which changes the final percentage.
Can I try The Baker before upgrading?
Yes. The Baker is free to download, and Pro tools can be evaluated before choosing subscription or lifetime Pro access in the app.
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Calculate sourdough hydration with less guesswork.
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