Yeast to sourdough converter
Enter your yeast recipe and your starter. You see how much starter to use under several published rules of thumb, and how much flour and liquid to take out so the dough keeps its hydration.
Result
Starter to use
g
Flour to use
g
Liquid to use
g
- How much starter replaces yeast is a rule of thumb, and published rules differ by two to three times. Treat the result as a starting point and watch the dough, not the clock.
| Flour in the starter | 100.0 g |
|---|---|
| Water in the starter | 100.0 g |
| Starter to use | 200.0 g |
| Flour to use = recipe flour − starter flour | 400.0 g |
| Liquid to use = recipe liquid − starter water | 225.0 g |
| Hydration of the yeast recipe | 65.0 % |
| Hydration with the starter | 65.0 % |
| Miss Vickie, normal same-day bread: lower end | 180.0 g |
| Miss Vickie, normal same-day bread: upper end | 250.0 g |
| Miss Vickie, fast same-day bread: lower end | 280.0 g |
| Miss Vickie, fast same-day bread: upper end | 350.0 g |
| Miss Vickie, overnight at room temperature: lower end | 100.0 g |
| Miss Vickie, overnight at room temperature: upper end | 160.0 g |
| Miss Vickie, cold-proofed pizza: lower end | 80.0 g |
| Miss Vickie, cold-proofed pizza: upper end | 140.0 g |
| Brod & Taylor: lower end | 75.0 g |
| Brod & Taylor: upper end | 100.0 g |
| The Pantry Mama, starter per packet of yeast | 100.0 g |
| The Pantry Mama, starter per packet of yeast | 100.0 g |
| The Fresh Loaf forum claim, starter per packet of yeast (unconfirmed) | 240.0 g |
| The Fresh Loaf forum claim, starter per packet of yeast (unconfirmed) | 240.0 g |
How it works
Starter is flour and water, so the calculator takes the starter's flour and water out of the recipe to keep the dough's hydration. The starter amount itself comes from published rules of thumb, shown side by side because they disagree.
Formula
Starter flour = p × F (or starter = p × F, or your starter weight). Starter = starter flour × (1 + h). Flour to use = F − starter flour. Liquid to use = L − starter water. Rules stated for a 100 % starter are converted by keeping their starter flour.
Worked example
The calculator opens with this example; the result above is computed from it.
| Input | Value |
|---|---|
| Flour in the recipe | 500 g |
| Liquid in the recipe | 325 g |
| Yeast in the recipe | 7 g |
| Starter hydration | 100 % |
| How to set the starter amount | Starter flour as a percentage of recipe flour |
| Starter percentage | 20 % |
| Starter to use | 200 g |
| Flour to use | 400 g |
| Liquid to use | 225 g |
For 500 g of flour and 325 g of liquid, 200 g of starter at 100 % brings 100.0 g of flour and 100.0 g of water. Use 400 g of flour and 225 g of liquid.
Assumptions and limits
- How much starter replaces yeast is not a measured conversion. Starters differ in strength, so every rule is shown as a range with its source.
- The default starter percentage lies inside Miss Vickie's range for normal same-day bread. It is an example, not a recommendation.
- Starter percentage means starter flour as a share of the recipe's total flour, as Miss Vickie defines it, unless you pick starter weight instead.
- Rules written for a starter with equal flour and water are applied to your starter by keeping the same amount of starter flour.
- Rules given per packet of yeast are scaled in proportion to the yeast in your recipe.
- Milk and other thin liquids are counted like water.
- Sourdough rises much more slowly than yeast dough. The calculator does not predict rise times.
The result is an estimate for planning, not professional advice.
Sources
- Miss Vickie: sourdough starter replacement calculator (inoculation = starter flour as % of total flour; adjusted flour / liquid; ranges per schedule)retrieved 2026-10-12
- Brod & Taylor: how to convert a yeast recipe to sourdough (15-20 % of flour weight, 100 % starter)retrieved 2026-10-12
- The Pantry Mama: 100 g starter ~ 7 g yeast, reduce flour 50 g and water 50 gretrieved 2026-10-12
- The Fresh Loaf forum comment (2009): 240 g of 100 % starter ~ one 7 g packet (unconfirmed)retrieved 2026-10-12
Last updated:
Method in depth: Baker's percentage: how bread formulas are written and scaled
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