How to use it
- Enter the Total flour of the dough, in grams.
- Enter the Hydration of the whole dough and the Levain (% of total flour) with its own Levain hydration.
- Enter the Salt as a percentage of the total flour.
- Weigh the Flour to add, Water to add, the levain and the salt. The table shows every amount as a baker's percentage.
How the amounts are worked out
Baker's percentages express every ingredient as a share of the flour, which is always 100 %. The levain is part of the flour and the water: its flour is its weight divided by one plus its hydration, and its water is the rest. The amounts to add are the totals minus what the levain already holds.
levain = total flour × levain %
levain flour = levain ÷ (1 + levain hydration)
levain water = levain − levain flour
flour to add = total flour − levain flour
water to add = total flour × hydration − levain water
salt = total flour × salt %- Hydration is the water as a percentage of the flour. The baker's percentage definition is in the Wikipedia article on baker's percentage.
- A levain at 100 % hydration holds equal weights of flour and water, so a 200 g levain holds 100 g of each.
- If the water to add is negative, the levain already has more water than the total hydration allows; the page shows a message.
What this calculator does not cover
- The mixing and folding schedule, and the time the dough rises. These depend on the temperature of your kitchen.
- Enriched doughs with milk, eggs, butter or sugar. Those ingredients are not counted here.
- The bake. See the recipe for oven temperature and time.
Worked example: 1,000 g flour, 75 % hydration
The levain is 20 % of 1,000 g, so 200 g. At 100 % hydration it holds 100 g flour and 100 g water. The total water is 75 % of 1,000 g, or 750 g, so 650 g of water is added. The flour to add is 1,000 − 100 = 900 g, and the salt is 2 % of 1,000 g, or 20 g.
The whole dough weighs 900 + 650 + 200 + 20 = 1,770 g.
| Ingredient | Grams | Baker's % |
|---|---|---|
| Flour to add | 900 | 90.0 |
| Water to add | 650 | 65.0 |
| Levain | 200 | 20.0 |
| Salt | 20 | 2.0 |
Frequently asked questions
What is the hydration of a sourdough dough?
It is the weight of all the water as a percentage of all the flour, including the flour and water in the levain. Most loaves are made between about 65 % and 80 %, but the right figure depends on the flour.
Why do I subtract the levain from the flour and water?
The levain already holds flour and water, so it counts toward the totals. Adding the full totals would count them twice; the calculator subtracts what the levain holds.
What does 100 % levain hydration mean?
The levain has equal weights of water and flour. A 100 % levain of 200 g is 100 g flour and 100 g water; a stiffer levain has less water.
How much levain should I use?
That depends on how long the dough rises and how warm the kitchen is. This calculator takes the percentage you choose and does not suggest one.
Why does the message say the levain has too much water?
The levain holds more water than the total hydration allows, so the water to add would be negative. Raise the hydration or use a smaller or stiffer levain.
Sources
Figures and text last checked on Tuesday, November 10, 2026.