Sourdough Starter Ratio Calculator

Express an ingredient in sourdough starter as a baker’s percentage of flour weight. Enter your own quantities and see the worked example.

How to use Sourdough Starter Ratio Calculator

1. Enter Ingredient Weight, Flour Weight in the matching stated or selected unit. 2. Use the same weight unit for ingredient and flour. Flour is the 100% reference, not the total batch weight; percentages can exceed 100%. The tool handles the entered ingredient and flour weights only. It does not infer a feeding ratio, fermentation readiness or flour and water contained in an existing starter. 3. Select Calculate or press Enter to see the result. 4. Select Select Copy result to copy the answer, or Reset to clear the form.

Why use this tool?

Use this tool to express an ingredient in sourdough starter as a baker’s percentage of flour weight. Define the flour basis explicitly. If you need total hydration, account for the flour and water in the starter before entering totals.

How the calculation works

Baker’s percentage = ingredient weight ÷ flour weight × 100. Use the same weight unit for ingredient and flour. Flour is the 100% reference, not the total batch weight; percentages can exceed 100%. The tool handles the entered ingredient and flour weights only. It does not infer a feeding ratio, fermentation readiness or flour and water contained in an existing starter. Decimal quantity arithmetic uses the entered values before display rounding. Quantities use up to six decimal places; smaller nonzero results use scientific notation. Currency uses the selected currency’s minor unit. Inputs and numeric results are bounded by magnitude 9,007,199,254,740,991. Baker’s percentage reference: https://www.kingarthurbaking.com/pro/reference/bakers-percentage

Example

Sourdough Starter example: 325 g of an ingredient ÷ 500 g flour × 100 = 65%.

Practical tip

Define the flour basis explicitly. If you need total hydration, account for the flour and water in the starter before entering totals.