Sourdough Starter Calculator
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Feeding ratios express flour, water, and starter as parts by weight. A 1:1:1 feed uses equal weights of starter, flour, and water. A 1:2:2 feed doubles flour and water relative to starter.
Flour = Starter × (Flour ratio / Starter ratio)After feeding, total starter weight equals the sum of carryover starter, new flour, and new water. Discard excess if you need a specific final amount.
Total = Starter + Flour + WaterHigher hydration and warmer temperatures speed fermentation. A 1:1:1 feed at 75°F peaks in 4–6 hours; 1:2:2 at the same temperature peaks in 6–10 hours.
Updated: July 2026
Refresh 50g starter with 50g flour and 50g water for 150g total. Discard all but 50g before feeding to keep starter volume manageable.
Build 30g starter + 60g flour + 60g water = 150g active levain. Ready to use when doubled and domed, typically 6–8 hours at 72°F.
Feed 20g starter with 40g flour and 40g water (1:2:2), store in fridge. Remove and feed twice at room temp before baking day.
A cup of starter weighs differently than a cup of flour. Always use a kitchen scale for 1:1:1 ratios. Even 10g errors compound over multiple feeds.
Adding flour and water to an unfed starter dilutes the culture unevenly and creates too much total volume. Always discard down to your carryover amount before feeding.
Maintaining a healthy sourdough starter requires consistent feeding ratios by weight, not volume. This calculator scales flour, water, and carryover starter for any refresh schedule so your starter stays active for baking.