Sourdough Hydration Calculator
450 g flour, 300 g water, 100 g starter at 100% hydration and 10 g salt give 500 g total flour and 350 g total water, so the loaf is 70% hydration, not the 66.7% you get without the starter. For a 900 g dough at 75% with 20% starter, mix 457.6 g flour, 330.5 g water, 101.7 g starter and 10.2 g salt.
How to use
- In "Find hydration", enter the flour, water, starter and salt you add to the bowl, in grams.
- Enter the starter hydration: 100 for a starter fed equal weights of flour and water, 50 for a stiff one.
- Read the true hydration, then the baker's percentage table and the flour and water hidden inside the starter.
- To plan a loaf, switch to "Plan a loaf". Enter the hydration you want, the total dough weight, the starter as a percent of total flour and the salt percent.
How it works
The flour and water in a starter count toward the loaf. Starter flour = starter weight / (1 + starter hydration / 100), and starter water = starter weight - starter flour. A 100 g starter at 100% hydration holds 50 g flour and 50 g water.
Total flour = added flour + starter flour. Total water = added water + starter water. Hydration = total water / total flour x 100. For 450 g flour, 300 g water and 100 g starter at 100%, total flour is 500 g, total water is 350 g and hydration is 70%.
Baker's percentages are every ingredient divided by total flour, so flour is 100%. Starter is shown as its full weight over total flour (the usual "starter %"), and the share of flour that comes from the starter is shown as pre-fermented flour.
Target mode runs the same maths backward. Total dough = total flour x (1 + hydration + salt%), so total flour = dough weight / (1 + hydration/100 + salt%/100). Starter weight = total flour x starter %, and the flour and water you add are the totals minus what the starter already holds.
Results are arithmetic on the numbers you enter. Flour absorbs water differently by type and the final feel of the dough also depends on temperature and fermentation, so treat the percentage as a starting point.
Typical hydration ranges
These ranges are common baking conventions, not fixed rules. Whole grain flours drink more water, so the same hydration feels stiffer.
| Loaf | Total hydration | Handling |
|---|---|---|
| Bagels, stiff doughs | 50-60% | Firm, easy to shape |
| Sandwich and country loaves | 65-75% | Soft, manageable |
| Open-crumb sourdough | 75-85% | Sticky, needs folds |
| Ciabatta-style | 80-90% | Very wet, little shaping |
FAQ
Does the starter count toward hydration?
Yes. A starter is made of flour and water, so both belong in the total. Leaving it out understates the hydration, most when you use a lot of starter.
What starter hydration should I enter?
Use 100 if you feed the starter equal weights of flour and water, which is the most common method. A stiff or Italian-style starter is often 50 to 60. Enter the value from your own feeding routine.
What is a good hydration for sourdough?
Many home bakers start at 65 to 70% and move toward 75 to 80% as handling improves. There is no best number, since flour type and shaping skill matter more than the target.
Is the starter percentage based on total flour?
Here it is the starter weight divided by total flour, including the flour inside the starter. Some recipes use added flour only, so check which one yours uses before comparing numbers.
Does salt change the hydration?
No. Hydration is only water over flour. Salt is shown as a baker's percentage, with 2% of total flour a widely used amount.