Bread Flour Hydration Converter
Convert between dough hydration percentage and water weight — find your current hydration and the water needed to hit a target.
How it works
Hydration % = water ÷ flour × 100 · Water for target = flour × target% ÷ 100 (baker’s percentages)
Hydration is the baker's percentage of water relative to flour weight, and it is the single biggest lever on crumb and handling. Low-hydration doughs (55–65%) are stiff and easy to shape for sandwich loaves and bagels, while high-hydration doughs (75–85%+) give the open, airy crumb of ciabatta and rustic sourdough but are stickier to work. Because it is a ratio by weight, the same percentage behaves consistently whether you mix 500 g or 2 kg of flour.
Worked example
Your recipe has 500 g flour and 350 g water: hydration is 350 ÷ 500 × 100 = 70%. To move to a 75% dough you need 500 × 75 ÷ 100 = 375 g water, so you add 25 g more water.
Frequently asked questions
What is a good hydration for a first sourdough?
Around 70% is forgiving — wet enough for a decent open crumb but still shapeable by hand. As you gain confidence you can push toward 75–80% for a more open, artisan-style crumb.
Does hydration count water only, or milk and eggs too?
In strict baker’s math, hydration is the total liquid weight (water, milk, and the water fraction of eggs) divided by flour. For simplicity this converter treats the "water" field as your total added liquid.
Why weigh instead of measuring cups?
A cup of flour can vary 15–20% by weight depending on how it is scooped, which throws off hydration badly. Weighing flour and water in grams makes the ratio exact and repeatable.
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This calculator is for educational purposes. Double-check important results before acting on them.