How to use it
Enter everything you weigh into the bowl: the flour, the water, the starter (or levain) and, if you like, the salt. Set the starter's hydration. If you feed it equal weights of flour and water, that is 100%. The result updates as you type.
Why your starter changes the number
Hydration is the weight of all the water in a dough divided by the weight of all the flour. A starter is just flour and water that has fermented, so both of its halves belong in that sum. Recipes that quote hydration as "water added divided by flour added" leave the starter out, which understates how wet the dough really is.
Worked example. 300 g flour, 200 g water and 100 g of a 100% starter.
Ignoring the starter: 200 ÷ 300 = 66.7%. Counting it: the starter adds 50 g flour and 50 g water, so (200 + 50) ÷ (300 + 50) = 250 ÷ 350 = 71.4%. That 5-point gap is the difference between a dough that feels manageable and one that spreads.
The formula
Starter flour = starter ÷ (1 + starter hydration)
Starter water = starter − starter flour
True hydration = (water + starter water) ÷ (flour + starter flour) × 100
Salt and starter are also shown as percentages of total flour, which is how bakers compare recipes regardless of loaf size.
What different hydrations feel like
These are rough guides, not rules. Whole-grain and freshly milled flours absorb more water than white bread flour, so the same number feels stiffer with them.
| True hydration | What to expect |
|---|---|
| Below 65% | Firm and easy to shape; tighter crumb. Common for sandwich loaves and bagels. |
| 65% to 75% | The range most home sourdough recipes sit in: workable, with an open but even crumb. |
| 75% to 85% | Slack and sticky; rewards strong flour and practised shaping with a more open crumb. |
| Above 85% | Very wet doughs such as ciabatta and focaccia, usually shaped minimally or baked in a pan. |
Limits of this calculator
- Ingredients that carry water, such as milk, yoghurt, eggs, honey or soaked grains, are not counted. Add their water content to "water added" if you want them included.
- Inclusions like seeds, cheese and fruit do not change hydration, but they do change how the dough feels.
- Hydration describes the recipe, not your flour. Two flours at the same hydration can behave very differently.
Questions
Does salt count towards hydration?
No. Salt is a separate baker's percentage, usually around 2% of total flour. It is shown here so you can check it.
My starter is stiff. What hydration do I enter?
Divide the water you feed it by the flour you feed it. Feeding 50 g flour and 25 g water gives a 50% starter. The starter feeding calculator works this out for any ratio.