Take a dough containing 400 g white flour, 50 g whole-wheat flour, 375 g water, 11 g salt, and 100 g 100%-hydration starter. The starter contributes 50 g flour and 50 g water. Total flour is 400 + 50 + 50 = 500 g; total water is 375 + 50 = 425 g. Divide 425 by 500 and multiply by 100: the final dough is 85% hydration.
Worked example with numbers
Identify the starter hydration before counting it. A 100%-hydration starter has equal flour and water by mass; a 60%-hydration starter has 60 g water for every 100 g flour. For any starter, split its total mass according to those parts, then add each contribution to the final dough totals. The dough hydration calculator helps calculate a stated flour-and-water formula, but the baker must include preferment ingredients in the inputs.
How to make the calculation
Keep flour and water in grams. Salt, yeast, oil, seeds, and inclusions affect dough behaviour but do not belong in the hydration denominator unless a recipe explicitly defines a different calculation. Record whether a levain, poolish, or starter is included in the stated flour amount. This avoids comparing one baker’s “75% hydration” excluding starter with another baker’s total-dough 75%.
Check the units and assumptions
Do not divide only the final-mix water by only the final-mix flour when starter is part of the loaf. Do not assume all starters are 100% hydration from their appearance. Do not add the whole starter mass to both flour and water; that doubles it. Do not use cup measures for this calculation: hydration is a mass ratio, and a cup of flour is not a fixed mass without a specific measuring convention.
Common mistakes
Hydration predicts neither a guaranteed crumb nor a required amount of water for every flour. Whole-grain flour, protein level, milling, temperature, fermentation, mixing, and handling change how a dough feels. A high percentage can be manageable in one formula and slack in another. Use the result to describe the formula and compare like recipes; adjust water during mixing only with a note of what changed.
When this result does not apply
King Arthur Baking defines hydration as water weight divided by flour weight and explicitly says flour and water in a sourdough preferment count in the final total. Its bread-hydration explanation gives a 100 g preferment example with 50 g flour and 50 g water.
Source for the external fact
Check the percentage with the hydration calculator, scale flour and water together in the recipe scaler, and convert a legacy volume recipe cautiously with the cups-to-grams converter.
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