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Bread Dough Hydration Calculator

Calculate bread dough hydration percentage, or find the water needed for a target hydration.

Result

Water Needed
350g

Hydration is expressed as a percentage of the flour weight (baker's percentage): water weight ÷ flour weight × 100. Higher hydration doughs are stickier and harder to handle but produce a more open, airy crumb; lower hydration doughs are easier to shape but denser.

About the Bread Hydration

The Bread Dough Hydration Calculator converts a target hydration percentage into the exact grams of water a baker needs for a given flour weight. Bakers describe and scale bread formulas using hydration percentage rather than a fixed water volume, since it stays consistent no matter how large or small the batch is. This tool is for anyone following a formula written in baker's percentages who needs an actual gram figure to weigh out at the mixing bowl.

How It Works

Enter the total flour weight in grams and the target hydration percentage. The calculator converts the percentage to a decimal and multiplies it by the flour weight to produce the water weight, rounded to the nearest gram. The single output is the water amount needed, in grams, to reach that hydration level for the flour weight entered.

Water (g) = Flour Weight (g) x (Target Hydration % / 100)

Formula & Methodology

Baker's percentage always treats flour weight as the fixed 100% baseline, and every other ingredient, including water, salt, and yeast, is expressed as a percentage of that flour weight rather than of the total dough weight. To work this out by hand, convert the hydration percentage to a decimal (70% becomes 0.70) and multiply directly by the flour weight in grams: 500g of flour at 70% hydration is 500 x 0.70 = 350g of water. This convention is what lets a formula written for a small home batch scale cleanly to a large commercial one using the same ratios.

Examples

Artisan Rustic Loaf

500g of flour at 70% target hydration, a common range for an open-crumb artisan loaf, requires 500 x 0.70 = 350g of water.

Sandwich Bread

1,000g of flour at 62% hydration, closer to a typical enriched sandwich loaf, requires 1,000 x 0.62 = 620g of water.

Advantages

  • Removes the mental math of converting a hydration percentage into a measurable water weight, especially when scaling a recipe up or down.
  • Uses baker's percentage, the same convention professional bread formulas are written in, so the result plugs directly into standard recipes without extra conversion.
  • Makes it fast to test how a small hydration change, such as moving from 65% to 70%, affects the water amount for a specific flour weight.

Common Mistakes

  • Treating hydration percentage as a share of total dough weight instead of flour weight, which produces the wrong water amount for any dough that is not an equal mix of the two.
  • Ignoring the water contributed by other wet ingredients, such as eggs or a levain, when trying to match a recipe's stated overall hydration level.
  • Assuming a higher hydration number automatically produces a better loaf, without adjusting handling technique, since wetter doughs need different mixing, folding, and shaping approaches.

Edge Cases to Watch For

  • The calculation only converts flour weight and hydration percentage into water weight; it does not add in moisture already carried by eggs, milk, honey, or a liquid pre-ferment, so a recipe using those ingredients will have a higher effective hydration than the number shown here.
  • Because hydration is always calculated against flour weight rather than total dough weight, this figure is not directly comparable to a general liquid-to-solids ratio without a separate conversion.
  • The tool only works in one direction, from a target percentage to a water weight; it does not calculate the hydration percentage of an existing recipe from known flour and water weights.

Common Use Cases

  • Home bakers converting a favorite recipe to a different batch size while preserving the same dough consistency.
  • Bread bakers experimenting with hydration levels to move a formula toward a denser sandwich loaf or a more open, artisan crumb.
  • Recipe developers documenting a formula in standard baker's percentage format so others can scale it reliably.
Written & fact-checked by the Calculateus TeamLast updated August 5, 2026How we verify our formulas

Frequently asked questions

Why is bread hydration always calculated relative to flour weight, not total dough weight?

This is the standard baker's percentage convention used throughout professional and home baking, where flour is always treated as 100% and every other ingredient (water, salt, yeast, fat) is expressed as a percentage of that flour weight - it makes recipes easy to scale to any batch size and easy to compare across completely different total dough weights.

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Conclusion

Hydration percentage is the backbone of how bread formulas are written, compared, and scaled, and this calculator turns that percentage into a concrete water weight in a single step. Pair the result with a kitchen scale, since accurate bread hydration depends on weighing ingredients rather than measuring them by volume.