Start with the bake you want
Choose the number and weight of mixed dough pieces. The planner works back to total flour, water and salt, then separates the flour and water supplied by the ripe starter. Next it sizes one starter build to provide both the recipe amount and the reserve you want to keep. All quantities use grams.
A complete two-loaf example
Two 750 g pieces at 70% hydration and 2% salt need 872.09 g total flour, 610.47 g total water and 17.44 g salt. At 20% prefermented flour with 100% hydration starter, use 348.84 g ripe starter, add 697.67 g flour and 436.05 g water. For a 30 g reserve, build 378.84 g starter: a 1:2:2 feed uses 75.77 g seed, 151.53 g flour and 151.53 g water.
The feed controls starter hydration
The seed hydration and flour/water feeding ratio determine the ripe starter’s calculated hydration. A stiff seed refreshed with equal flour and water may still finish below 100%. The dough calculation uses that result rather than silently treating every starter as equal parts flour and water.
Save a recipe without an account
Save this project stores one draft for this tool in this browser. Load brings the draft back for recalculation; Delete saved draft removes it. A downloaded project file is another way to keep or move inputs. None of these actions uploads your recipe. Clearing browser data removes local drafts.
What is outside this recipe
The model has only flour, water, flour-and-water starter and salt. Enriched dough and inclusions need their own accounting. It estimates mixed dough before baking or handling loss. Observe fermentation and use a tested method; the planner does not predict peak times or certify food safety.
Questions, answered
Can I change loaf size without changing hydration?
Yes. Total dough changes while the selected flour-based ratios remain the same.
Does the reserve count in dough weight?
No. The feed makes recipe starter plus reserve, but only the recipe starter goes into the dough.
Further reading: King Arthur Baking: baker’s percentage. The examples and tools on this page use the assumptions stated above.