Hong Life CalculatorsUnderstanding the dough hydration calculator — concept and principle
Hydration is the weight of water in a dough expressed as a percentage of the weight of flour. It is the single number bakers use to describe how stiff or slack a dough is, and it lets you scale or compare recipes regardless of batch size. This calculator also counts the flour and water hidden inside a sourdough starter or levain, which is easy to forget and can shift the real hydration by several points.
How it is calculated
Total hydration = (water + water in starter) ÷ (flour + flour in starter) × 100.
A starter with hydration h % contains flour and water in the ratio 100 : h, so its flour share is starter × 100/(100 + h) and its water share is starter × h/(100 + h).
- Flour (g): the flour you add directly.
- Water (g): the water (or other liquid) you add directly.
- Starter (g): the weight of levain or starter added.
- Starter hydration (%): how wet the starter is; 100 % means equal weights of flour and water.
The principle
Bakers express every ingredient relative to total flour (baker's percentage), because flour is the structural base that absorbs water and forms gluten. A starter is simply pre-mixed flour and water, so treating it as a separate ingredient understates both the flour and the water. Splitting it back into its two parts gives the hydration the dough actually has.
Worked example
- Starter at 100 % hydration: 100 × 100/200 = 50 g flour and 50 g water.
- Total water = 350 + 50 = 400 g.
- Total flour = 500 + 50 = 550 g.
- Hydration = 400 ÷ 550 × 100 = 72.73 %.
Without counting the starter you would have calculated 350 ÷ 500 = 70 %, almost three points too low.
| Flour (g) | Total hydration |
|---|---|
| 125 | 228.57% |
| 250 | 133.33% |
| 375 | 94.12% |
| 500 | 72.73% |
| 625 | 59.26% |
| 750 | 50% |
| 1,000 | 38.1% |
How to read the result
- About 55–65 %: firm doughs such as bagels, many sandwich loaves and enriched doughs.
- About 65–75 %: typical everyday breads and many sourdough loaves.
- Above about 75 %: open, airy crumb (ciabatta, high-hydration country loaves) but sticky handling.
Whole-grain and freshly milled flours absorb more water, so the same percentage feels stiffer than with white flour.
Common mistakes
- Ignoring the starter, or entering the levain's hydration incorrectly.
- Forgetting other liquids such as milk, eggs or honey, which also carry water.
- Comparing hydration across very different flours as if they behaved the same.
Frequently asked questions
Should I count salt or yeast in the flour weight?
No. Only flour (including the flour in the starter) is the base; salt, yeast and other ingredients are expressed as percentages of it.
How do I count milk?
Whole milk is roughly 87–88 % water, so a common approach is to count about that share of its weight as water.
What if my starter is stiff, at 50 %?
Enter 50; the calculator then treats two-thirds of the starter as flour and one-third as water.
Sources: Jeffrey Hamelman, Bread: A Baker's Book of Techniques and Recipes (Wiley). · Wayne Gisslen, Professional Baking (Wiley) — baker's percentages.