What is this?
This calculator converts a baker's-percent starter percentage into the actual starter weight and breaks that starter into its flour and water components based on the starter hydration. It then calculates how much additional water you must add to reach your desired dough hydration. Baker's percent starter% is always relative to total flour weight; starter contributes both flour and water to the formula and must be counted in totals [1][2].
Why important: Ignoring the water in your starter will lead to mis-specified hydration: dough can end up too wet or too dry. Calculating starter flour and water precisely allows you to achieve the hydration you expect and predict handling and crumb outcome [1].
Calculator
Weight of starter needed based on percent of total flour
Part of total flour already present in the starter
Water already contributed by the starter
Amount of water to add to reach desired hydration (does not include water in starter)
Estimate including ~2% salt; starter components are already within flour and water totals
🛒 Recommended Products
We recommend the following tools for this recipe:
Digital Kitchen Scale
Essential for accurate measurement of flour and starter
Glass Jar for Starter
Good container for maintaining and feeding your starter
Jar Spatula
Handy for scraping starter out of jars cleanly
Dough Scraper/Bench Knife
Useful for dividing dough and folding during bulk ferment
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Recommendations by Flour Type
| Flour | Min % | Standard % | Max % |
|---|---|---|---|
| Typical bread flour | 65% | 68% | 72% |
| Whole wheat blends | 75% | 78% | 85% |
| Rye-containing doughs | 70% | 76% | 85% |
| Spelt | 60% | 64% | 68% |
Hydration Ranges
Slow fermentation, subtle acidity; useful for long proofs
Common range for predictable fermentation and flavor balance
Faster fermentation and stronger starter influence; watch dough temperature
Very active starter dominance — can dramatically shorten bulk ferment and increase acidity
Tips
💡 Always weigh on a scale
Weigh all ingredients on a kitchen scale. Small errors in starter or water cause big hydration shifts; digital scales give consistent results [1].
💡 Account for starter hydration
Remember the calculator includes the starter's flour and water. If your starter is 100% hydration (1:1), half its weight is water. Convert starter hydration accurately to avoid surprise dough consistency [1][2].
💡 Keep starter container and tools handy
Maintain your starter in a clear glass jar and use a jar spatula for clean transfers. This reduces waste and improves measurement accuracy [2].
💡 Adjust by feel and season
Flour absorption varies by brand and season — start a bit under target hydration and adjust. Warmer seasons often need slightly less added water [1].
💡 Check fermentation activity, not just numbers
Starter percentage affects fermentation speed; monitor dough rise and strength and adjust bulk ferment time rather than only adjusting starter% [1][2].