Sourdough Hydration Calculator
Calculate starter-aware sourdough hydration, total flour and water, and baker's percentages so you can compare formulas, tune dough handling, and scale a more repeatable loaf before mixing.
Sourdough Inputs
Sourdough Hydration Summary
Final hydration
72.7%
Total water divided by total flour
Starter contribution
100 g
50 g flour + 50 g water
Total flour
550 g
50 g from starter
Total water
400 g
50 g from starter
Salt
1.82%
Of total flour
Starter flour share
9.1%
Prefermented flour
Current Calculation
Starter flour = starter weight / (1 + starter hydration ratio)
100 / (1 + 1) = 50 g
Starter water = starter weight - starter flour
100 - 50 = 50 g
Total flour = added flour + starter flour
500 + 50 = 550 g
Total water = added water + starter water
350 + 50 = 400 g
Hydration = total water / total flour x 100
400 / 550 x 100 = 72.7%
Breakdown
| Added flour | 500 g |
| Starter flour | 50 g |
| Total flour | 550 g |
| Added water | 350 g |
| Starter water | 50 g |
| Total water | 400 g |
| Salt | 10 g (1.82%) |
| Starter flour share | 9.1% |
Use Scenarios
Compare inherited formulas
Check whether two recipes that look similar on paper really land at the same hydration after starter flour and starter water are counted.
Tune dough handling before mixing
Use the final hydration, total flour, and total water output to decide whether you are aiming for a tighter bench-friendly dough or a wetter open-crumb mix.
Translate between liquid and stiff starters
Swap starter hydration values to see why a formula written for a stiff levain often feels drier than one built around a 100% starter.
Formula Explanation
1) Split the starter
Starter flour = starter weight / (1 + hydration ratio)
A starter contributes both flour and water. A 100% starter has a hydration ratio of 1.00, so a 100 g starter contributes 50 g flour and 50 g water.
2) Add total flour and water
Total flour = added flour + starter flour
Direct flour and direct water are not the final totals on their own. The calculator adds starter contributions before it reports total dough hydration.
3) Compute final hydration
Hydration (%) = total water / total flour x 100
This is the main output that bakers compare across sourdough formulas. It describes the full dough system after starter water and flour are counted.
4) Read baker's percentages
Salt % and starter flour share are measured against total flour
Salt does not change hydration itself, but it is still shown as a baker's percentage. Starter flour share helps you compare how much of the flour is prefermented.
How to Read the Result
Final hydration
Use the headline percentage to compare formulas quickly. Upper-60s often feels easier to shape, while mid-70s and above usually demands stronger flour and tighter handling.
Total flour and water
These totals are the cleanest way to compare one recipe with another, especially when starter size changes and the direct-added flour and water no longer tell the full story.
Starter flour share and salt
Starter flour share shows how much of the flour is prefermented. Salt stays separate as a baker percentage because it seasons and tightens dough but does not count toward hydration.
Example Cases
Case 1: Controlled country loaf baseline
Inputs
- Flour 500 g
- Water 325 g
- Starter 100 g at 100%
- Salt 10 g
Computed Results
- Hydration: 68.2%
- Total flour: 550 g
- Total water: 375 g
- Salt: 1.82%
Interpretation
This lands in a relatively controlled range for many white-flour country loaves. It is wet enough to stay extensible without pushing hard into a sticky high-hydration workflow.
Decision Hint
Use a case like this as your baseline when you want to compare flour changes, fermentation timing, or shaping technique without changing multiple variables at once.
Case 2: Wetter open-crumb mix
Inputs
- Flour 500 g
- Water 350 g
- Starter 100 g at 100%
- Salt 10 g
Computed Results
- Hydration: 72.7%
- Total flour: 550 g
- Total water: 400 g
- Salt: 1.82%
Interpretation
Adding just 25 g more direct water lifts the dough into a noticeably wetter range. The formula is still manageable, but it usually benefits from stronger gluten development and cleaner folds.
Decision Hint
Choose a case like this when you are deliberately chasing more openness in the crumb and your flour can support a looser dough.
Case 3: Same mix, stiffer starter
Inputs
- Flour 500 g
- Water 350 g
- Starter 100 g at 60%
- Salt 10 g
Computed Results
- Hydration: 68.9%
- Total flour: 562.5 g
- Total water: 387.5 g
- Salt: 1.78%
Interpretation
Keeping the same direct flour and water but swapping to a stiffer starter lowers final hydration because the starter now contributes more flour than water.
Decision Hint
Use this comparison when you inherit a formula written for a stiff levain and want to understand why it feels tighter than a 100% starter version.
Boundary Conditions
Sources & References
- King Arthur Baking - Baker's PercentageUsed for the flour-equals-100% rule and the baker's-percentage framework behind the calculator's salt and starter-flour-share outputs.
- King Arthur Baking - Hydration in bread dough, explainedUsed for hydration definition, what ingredients do and do not count toward bread hydration, and why dough feel changes as water percentage rises.
- Brod & Taylor - Sourdough Starter 101Used for starter-hydration context, including the practical meaning of a 100% starter and the lower-water range commonly used for stiff starters.
- The Perfect Loaf - Baking Sourdough Bread with a Stiff StarterUsed as a supplementary explanatory reference for how lower-hydration starters change dough feel and why stiff-starter formulas often read drier.