Sourdough Starter Feeding Ratio Calculator
Use a feeding ratio and target hydration to calculate the grams of starter, flour and water to combine, plus total weight and discard.
Result
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Result
— g total
- Starter
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- Flour
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- Water
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- Discard
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How the sourdough starter feeding ratio calculator works
A sourdough starter feeding ratio calculator uses parts by weight written starter : flour : water. Enter the starter you are keeping or the total you want, then choose whether water follows the ratio or a target hydration.
For a fixed ratio, flour and water scale from the starter amount. Working backwards from a total first finds the starter portion. When hydration is selected, water is calculated from the flour amount, so you can adjust the water without changing the flour part of the ratio.
A 1:1:1 feed keeps a 100% hydration starter at 100%. Typical practice is 1:1:1 for a quick refresh at room temperature, while 1:5:5 or higher can slow fermentation before a long rest. Warmer kitchens ferment faster.
flour = starter × (b ÷ a); water = flour × hydration ÷ 100; total = starter + flour + water If you enter current starter, discard is current starter minus the amount kept. The numbers are parts by weight; use a scale for the measured grams.
Sourdough starter feeding ratio FAQ
What does 1:1:1 mean?
It means one part starter, one part flour and one part water by weight. For example, 20 g starter takes 20 g flour and 20 g water.
What feeding ratio should I use?
Use the ratio that matches your recipe or routine. Typical practice is 1:1:1 for a quick refresh at room temperature, while 1:5:5 or higher can slow fermentation before a long rest.
What is starter hydration?
Hydration compares water weight with flour weight. A 100% hydration starter has equal weights of flour and water; this calculator lets you derive water from the target percentage.
How is discard calculated?
When current starter is entered, discard is the current amount minus the starter amount you are keeping. If current starter is omitted, discard is shown as zero.
Why does a warmer kitchen matter?
Warmer kitchens ferment faster, so the same feeding ratio may need a different timing than it would in a cooler kitchen.