Plan a sourdough bake in grams. Set the flour, the hydration you want, how much starter you use and how wet it is, and the calculator gives the water, starter and salt to weigh out, counting the flour and water already inside the starter so your hydration is the true one.
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Start from
g
Per loaf. Mix of bread, whole wheat or rye flour all counts.
g
Final weight of the dough you want to shape.
%
Total water ÷ total flour, counting what is in the starter.
% of flour
Baker's % of the flour you add (10–25% typical).
%
100% = equal weights of flour and water. Stiff starters are 50–60%.
%
Water part scales with your starter hydration. Includes 10% extra for what sticks to the jar.
Enter your values to see the result.
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How to use the Sourdough Calculator
Choose what you know: the flour you add to the bowl, the total flour including the starter, or the dough weight you want per loaf.
Enter the flour or dough weight and the number of loaves.
Set hydration, starter % and starter hydration. 75% hydration, 20% starter and a 100% hydration starter are a good start.
Set the salt, usually 2% of the flour.
Weigh out the results: water to add, flour, starter and salt, and use the levain build line to feed your starter the right amount.
Sourdough formulas (baker's percentages)
All amounts are percentages of the total flour, including the flour inside the starter.
Starter = flour added × starter %. Its flour = starter ÷ (1 + starter hydration); its water = starter − its flour.
Total flour = flour added + flour in starter.
Water to add = total flour × hydration − water in starter.
Salt = total flour × salt %.
Dough weight = total flour × (1 + hydration + salt %), so total flour = dough ÷ (1 + hydration + salt %).
Example: 500 g flour, 20% starter at 100%, 75% hydration, 2% salt. Starter = 100 g (50 g flour + 50 g water). Total flour = 550 g. Total water = 550 × 0.75 = 412.5 g, so add 362.5 g water. Salt = 11 g. Dough = 500 + 100 + 362.5 + 11 = 973.5 g.
Hydration guide
Hydration
Dough feel
Typical use
60–65%
Stiff, easy to shape
Bagels, sandwich loaves, beginners
65–72%
Soft, manageable
Everyday sourdough, high whole wheat breads with more water
72–78%
Slack, a little sticky
Classic country loaf (boule or batard)
78–85%
Very wet, needs strength
Open crumb loaves, ciabatta-style
85%+
Batter-like
Focaccia, high-hydration ciabatta
Whole wheat, spelt and rye flours absorb more water than white bread flour, so a blend with 30% whole grain often behaves like a white dough 3 to 5 points lower in hydration.
Frequently asked questions
How do I calculate sourdough hydration?
Hydration is total water divided by total flour, times 100. Count the water and flour inside the starter. A 100% hydration starter is half flour and half water, so 100 g of starter adds 50 g flour and 50 g water.
Why is my sourdough wetter than the recipe hydration?
Many recipes quote hydration from the flour and water you add and ignore the starter. With 20% starter at 100% hydration, a recipe listed as 70% is really about 72.7%. This calculator always targets the true hydration.
How much starter should I use?
Most bakers use 10% to 25% starter relative to the flour. More starter ferments faster; less starter gives you more time and a milder flavor. In warm kitchens, 10% to 15% is easier to control.
What hydration is best for beginners?
Around 65% to 70% is easiest to shape. 72% to 78% is a typical country loaf, and 80% or more gives an open crumb but needs practice. Whole wheat and rye absorb more water, so they can take higher hydration.
How much salt goes in sourdough?
About 2% of the total flour weight, so 10 g for 500 g of flour. Most recipes use 1.8% to 2.2%.
What does a 1:2:2 levain build mean?
One part starter, two parts flour and two parts water by weight. For example 20 g starter + 40 g flour + 40 g water makes 100 g of levain. Higher ratios take longer to peak.
How do I make a specific dough weight?
Choose Target dough weight. Total flour = dough weight ÷ (1 + hydration + salt), because all ingredients are expressed relative to the total flour.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.