Count the starter
A 100 g starter at 100% hydration brings 50 g flour and 50 g water. Leaving it out changes the answer.
A little precision. A better bake.
Sourdough Hydration Calculator
Know your dough before your hands get sticky. Calculate true hydration—including the flour and water in your starter.
✓ Starter included✓ Free, no account
True dough hydration
72.73%True dough hydration
400 g
Total water÷550 g
Total flour
Total water÷550 g
Total flour
× 100
01 / Your dough, in numbers
Your dough, in numbers
Enter added ingredients only. We count the starter separately. All weights are in grams.
ⓘ 100% hydration means equal weights of flour and water, not equal volumes.
True dough hydration
72.73%
Total water ÷ total flour × 100
Total flour550 g
Total water400 g
Your ingredient list
- Added flour
- 500 g
- Added water
- 350 g
- Starter / levain
- 100 g
- Salt
- 10 g
Dough per loaf: 480 g
Nothing hidden in the numbers
- Flour in starter
- 50 g
- Water in starter
- 50 g
- Salt / total flour
- 1.82 %
- Prefermented flour
- 9.09 %
Baker's percentage view
- Total flour
- 100%
- Total water
- 72.73%
- Starter / levain / Total flour
- 18.18%
- Salt
- 1.82%
- Prefermented flour
- 9.09%
Runs in your browser. No account. Recipe values stay on your device unless you copy and share them.
Compare water targets
Same flour and starter. These are calculated amounts, not recommendations for every flour.
ADVANCED DOUGH MATH
Change starter hydration without changing the final dough hydration
Keep the starter weight, total flour and total water the same while converting between a liquid and stiff starter. The tool tells you how the added flour and added water must change.
Adjusted added ingredients
- New added flour
- 487.5 g
- New added water
- 362.5 g
- Final hydration stays
- 72.73%
- Flour in new starter
- 62.5 g
- Water in new starter
- 37.5 g
This preserves total flour and total water. It does not convert fermentation strength, maturity or feeding schedule.
FORMULA EXPLORER
Starter percentage and prefermented flour are not the same number
Enter added flour, starter weight and starter hydration. The tool separates flour from water inside the starter before calculating both percentages.
- Flour inside starter
- 50 g
- Total flour
- 550 g
- Starter weight / total flour
- 18.18%
- Prefermented flour / total flour
- 9.09%
Starter percentage uses the whole starter weight. Prefermented-flour percentage uses only the flour inside the starter. Neither number predicts fermentation time by itself.
02 / The baking notes
A number is a starting point.
Your flour, technique and fermentation still have a say. Here is how to make the number useful.
Work by weight
A cup of flour can vary. A scale makes your formula easier to compare, repeat and adjust.
Change one thing
Keep a note of your flour and process. Small, deliberate changes teach more than chasing a bigger percentage.
03 / Journal
A better next bake
Prefermented flour vs starter percentage: they are not the same number
Understand two common sourdough percentages, calculate both from the same formula, and see why starter hydration changes one of them.
Read the guide ↗How to change starter hydration without changing final dough hydration
Convert a liquid starter to a stiff starter—or back—while keeping the same total flour, total water and final hydration.
Read the guide ↗How to calculate sourdough hydration with starter
Count the flour and water in your starter, check a worked example, and avoid confusing starter percentage with dough hydration.
Read the guide ↗How to adjust sourdough hydration without guessing
Work out the water needed for 65%, 70% or 75% hydration, including starter, and make controlled changes between bakes.
Read the guide ↗How to scale a sourdough recipe for two loaves
Scale flour, water, starter and salt by the same factor, preserve hydration, and distinguish dough weight from baked bread weight.
Read the guide ↗A few things worth knowing.
What does 75% hydration mean?
Water weighs 75% of the total flour. With 550 g total flour, 75% hydration means 412.5 g total water, including the water in your starter.
Is higher hydration always better?
No. Hydration does not score the quality of a loaf. Flour absorption, mixing, fermentation and shaping all affect the result. Choose a dough you can handle and adjust gradually.
Does salt count as flour or water?
No. Salt contributes to dough weight and has its own baker’s percentage, but it does not enter the water-to-flour ratio.
Can I include milk, eggs, oil or soaked seeds?
This tool assumes a flour-and-water starter and plain added water. It does not estimate the water in enriched ingredients or soaked inclusions. Those need a separate calculation.