Sourdough Calculator

Scale a Sourdough Recipe by Hydration

This sourdough calculator turns flour weight, dough hydration, starter percentage, salt percentage, and starter hydration into water, starter, salt, and total dough weight. It also shows how much flour and water live inside your starter. Pair it with the Perfect Pizza Calculator, Rice Water Ratio Calculator, and Cups to Grams Converter.

Core Formulas

Water follows baker's percentages from the flour you enter. Starter weight is a percent of that same flour. Salt is usually about 2% of flour weight for bread.

$$\text{water (g)} = \text{flour (g)} \times \dfrac{\text{hydration}}{100}$$

$$\text{starter (g)} = \text{flour (g)} \times \dfrac{\text{starter \%}}{100}$$

$$\text{starter flour (g)} = \dfrac{\text{starter (g)}}{1 + \dfrac{\text{starter hydration}}{100}}$$

$$\text{total hydration (\%)} = \dfrac{\text{water} + \text{starter water}}{\text{flour} + \text{starter flour}} \times 100$$

Starter Hydration Matters

A 100% hydration starter is half flour and half water by weight. A stiff 50% starter carries less water, so total dough hydration drops even when the recipe hydration looks high. Adjust starter hydration to match your levain and the calculator splits starter flour and starter water for you.