Sourdough Hydration Calculator
True hydration of your dough, counting the flour and water in the starter.
Updated · How we check our maths
- True hydration
- 72.7%
- Total flour (incl. starter)
- 550 g
- Total water (incl. starter)
- 400 g
- Salt
- 1.8% of flour
- Starter (inoculation)
- 20% of flour
- Total dough weight
- 960 g
- Water to add for 75%
- 363 g (+13 g)
Quick answer
Hydration = total water ÷ total flour × 100, where the totals include the flour and water inside your starter. 500 g flour, 350 g water and 100 g of 100% starter is 400 ÷ 550 = 72.7% — not the 70% you'd get by ignoring the starter.
What the Sourdough Hydration Calculator does
Enter your recipe weights and your starter's hydration. The calculator splits the starter into flour and water, gives the true dough hydration, salt percentage, starter (inoculation) percentage and dough weight, and tells you how much water to use for a target hydration.
65–70% hydration is easy to handle; 75–80% gives a more open crumb but a stickier dough. Whole-grain flours absorb more water.
The formula
Starter flour = starter ÷ (1 + starter hydration); starter water = starter − starter flour. Hydration = (water + starter water) ÷ (flour + starter flour) × 100.
Worked example
1,000 g flour, 780 g water, 200 g starter at 100%: (780 + 100) ÷ (1,000 + 100) = 80%.
How to use the Sourdough Hydration Calculator
- Weigh flour, water, starter and salt in grams.
- Enter your starter's hydration (100% = equal flour and water).
- Optionally set a target hydration to get the water needed.
Frequently asked questions
What hydration is best for sourdough?
Most loaves are 68–78%. Beginners often find 70% easiest.
Should I include the starter in hydration?
Yes, for true hydration — a 20% starter adds noticeable water and flour.
How much salt for sourdough?
Usually 1.8–2.2% of total flour weight.
Results are estimates for planning and learning. Check important figures with a qualified professional. How we build and check our calculators.