Sourdough Calculator
Plan a sourdough bake from flour or dough weight and hydration, correctly subtracting the flour and water your starter already contains.
Processed locally in your browser — nothing is uploaded.
Sourdough Calculator
Includes the flour inside the starter.
As a percentage of total flour.
Most starters are fed 1:1 flour:water — 100%.
Results
- Flour to add
- 900 g
- Water to add
- 650 g
- Starter
- 200 g
- Salt
- 20 g
- Total dough
- 1,770 g
Carries 100 g flour + 100 g water, already subtracted above.
Overall hydration counts the water inside the starter, so the dough comes out exactly as specified.
About Sourdough Calculator
The trap in sourdough math is the starter: a 100%-hydration starter is half flour and half water, and if you don't subtract that from the recipe your real hydration drifts. This calculator treats starter flour and water as part of the totals, so the dough you mix hits the hydration you asked for exactly.
Solve from either a total flour weight or a target dough weight, and set the starter's own hydration if you keep a stiff levain.
Common uses
- Mix a 75% hydration loaf that is actually 75% after adding starter
- Hit an exact final dough weight for a specific banneton or tin
- Adapt a recipe written for a liquid starter to your stiff one
Example
Input
1000 g total flour · 75% hydration · 20% starter (100%) · 2% salt
Output
Add 900 g flour + 650 g water + 200 g starter + 20 g salt = 1770 g dough
Frequently asked questions
Why does sourdough starter mess up hydration math?
Because starter is itself flour and water: 200 g of a 100%-hydration starter carries 100 g of flour and 100 g of water. If a recipe ignores that, the dough's real hydration lands higher or lower than the stated percentage — this calculator subtracts the starter's contents so it comes out exact.
What does 20% starter mean in a sourdough recipe?
Starter weight equal to 20% of the total flour weight, following baker's percentage convention. For 1000 g of total flour that is 200 g of starter, counted as part of the flour and water totals rather than on top of them.
What if my starter isn't 100% hydration?
Set the starter's own hydration in the calculator and it splits the starter accordingly — a stiff 50%-hydration levain is two-thirds flour and one-third water, not half and half, so the flour and water you add change too.
How is the final dough weight calculated?
Total flour times 1 plus the hydration and salt percentages. In the example, 1000 g flour at 75% hydration with 2% salt gives 1000 + 750 + 20 = 1770 g of dough; the starter is already inside those totals.
Is my sourdough formula sent to a server?
No. The levain accounting happens in your browser with JavaScript; your amounts are never uploaded or stored.