Last reviewed: 2026-08-04
Hydration calculator
Sourdough hydration calculator
Calculate true dough hydration from flour, water, starter weight, and starter hydration. The math includes the flour and water inside your levain.
Sourdough hydration is total water divided by total flour, including the water and flour contributed by the starter. A dough with 700g total water and 1,000g total flour is 70% hydration.
Calculate dough hydration
The exact hydration formula
Starter flour = starter weight ÷ (1 + starter hydration ÷ 100). Starter water = starter weight − starter flour.
True dough hydration = (recipe water + starter water) ÷ (recipe flour + starter flour) × 100.
Solved example: why starter changes the result
Recipe: 900g flour, 650g water, and 200g starter at 100% hydration.
The starter contributes 100g flour and 100g water, so the totals are 1,000g flour and 750g water. True hydration is 75%, not 72.2%.
What counts as water in this calculator?
| Ingredient | How to enter it | Why |
|---|---|---|
| Water or melted ice | Add to recipe water | It contributes directly to hydration. |
| Starter or levain | Use the starter fields | Its flour and water must be split according to starter hydration. |
| Flour, whole grain, or rye | Add to recipe flour | Different flours absorb water differently, but all count toward total flour. |
| Salt and oil | Do not add to water | They affect dough feel but are not water in baker’s-percentage hydration. |
| Milk, eggs, fruit, or cheese | Treat the result as a baseline | These ingredients contain varying amounts of water, fat, and solids; this simple calculator does not estimate their effective water. |
How hydration is calculated
- Baker’s percentage treats total flour as 100%. Water percentage is measured against that flour total.
- A 100% hydration starter is half flour and half water by weight.
- The calculator adds starter flour to recipe flour and starter water to recipe water before dividing.
Hydration guidelines
- Beginner sourdough often feels easier around 65% to 72% hydration.
- Very high hydration doughs need stronger flour and gentler handling.
- Whole wheat and rye absorb more water than white bread flour.
- Changing starter hydration changes the true dough hydration.
FAQ
How do I calculate sourdough hydration?+
Divide total water by total flour and multiply by 100. Include the water and flour inside your starter.
Do I include starter in hydration?+
Yes. Starter contains both flour and water, so excluding it makes the final hydration inaccurate.
What is 70% hydration sourdough?+
It means the formula has 70g water for every 100g flour, after including starter flour and water.
What hydration is best for beginners?+
Many beginners do well around 65% to 72% because the dough is easier to mix, fold, and shape.