Sourdough Calculator

Written by Great Medico

Updated September 25, 2026 •2 min read

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The Sourdough Calculator turns a practical cooking or serving question into a repeatable calculation. Its job is to calculate total dough, starter contribution, and overall hydration from flour, water, starter mass, starter hydration, and salt. Instead of pretending every kitchen behaves identically, the calculator exposes the values it uses so you can replace the defaults with numbers that fit your food, equipment, or event.

What this calculator does

The Sourdough Calculator uses the fields on this page to calculate total dough, starter contribution, and overall hydration from flour, water, starter mass, starter hydration, and salt. Its primary output is labeled “Sourdough baker’s math” and is displayed in g total dough. Supporting readouts include Percentage starter, Starter flour, Starter water.

How to use it

Enter flour, water, starter mass, salt, and starter hydration. The current calculation derives starter percentage from starter mass divided by flour mass; changing the separate starter-percentage field by itself does not change the result.

How the calculation works

Starter is split into flour and water from its hydration. Total flour = recipe flour + starter flour; total water = recipe water + starter water; dough hydration = total water ÷ total flour × 100; total dough adds flour, water, starter contribution, and salt. The displayed starter percentage is calculated from starter mass ÷ flour mass rather than taken from the editable starter-percentage field.

Example

With Percentage starter = 20 %, Flour = 500 g, Water = 350 g, the calculator returns 960 g total dough for “Sourdough baker’s math.” The same run also shows Percentage starter = 20%; Starter flour = 50 g; Starter water = 50 g; Total flour = 550 g. Changing one input at a time makes it easy to see which assumption is driving the result.

How to interpret the result

For the Sourdough Calculator, read the result as a process-calculation target. Small changes in measurement can matter, so keep the original inputs with the result and use appropriate brewing, winemaking, or baking measurements when precision affects the finished product.

Limitations and notes

The editable starter-percentage field is not used to drive the current calculation; the page recomputes starter percentage from starter mass ÷ flour mass. If you want a specific inoculation percentage, adjust the starter mass itself and verify the displayed percentage.