Sourdough Ratio Calculator (Baker's Percentages)
Turn baker's percentages into exact gram weights for flour, water, starter and salt.
Reviewed by the Calculation Machine team · Updated 24 October 2026 · How we check our maths
Your values
ⓘ Live results
- Flour to add
- 450 g
- Water to add
- 325 g
- Starter
- 100 g
- Salt
- 10 g
- Total dough weight
- 885 g
- Overall hydration
- 75 %
Starter flour and water are counted in the totals.
| Ingredient | Grams | Baker's % |
|---|---|---|
| Flour (total) | 500 | 100% |
| Water (total) | 375 | 75% |
| Starter | 100 | 20% |
| Salt | 10 | 2% |
Quick answer
In baker's percentages every ingredient is a share of the total flour weight, which is 100%. For 500 g flour at 75% hydration, 20% starter and 2% salt you need 375 g total water, 100 g starter and 10 g salt. Because a 100%-hydration starter is half flour and half water, you add only 450 g flour and 325 g water to the starter.
What the Sourdough Ratio calculator does
Enter the total flour for your loaf, the hydration you want, the starter (levain) percentage, salt percentage and your starter's own hydration. The calculator gives the flour and water to add on top of the starter, the starter and salt weights, total dough weight and overall hydration, with the starter's flour and water already counted.
This is the way most sourdough formulas are written, and it lets you scale any recipe or change one variable at a time. A 75% dough made with 500 g flour gives one standard loaf of about 885 g; double the flour for two. For yeasted pizza and flatbread doughs, the pizza dough hydration calculator adds yeast to the same method, and the recipe scaling calculator helps with recipes written in cups.
Hydration on paper is not the whole story. Whole-wheat, rye and freshly milled flours absorb more water than white bread flour, so the same percentage gives a stiffer dough. Start lower and add water in later stages if the dough feels tight.
The formula
Starter = F × s Starter flour = starter ÷ (1 + h_s) Starter water = starter − starter flour Total water = F × h Salt = F × salt% Flour to add = F − starter flour Water to add = total water − starter water
| Symbol | Meaning | Unit |
|---|---|---|
| F | Total flour in the dough, including the flour inside the starter | g |
| h | Target overall hydration (water ÷ total flour) | % |
| s | Starter weight as a percentage of total flour | % |
| h_s | Starter hydration: 100% means equal weights of flour and water | % |
| salt% | Salt as a percentage of total flour | % |
Baker's percentages are the standard professional method taught by the Bread Bakers Guild of America and in texts such as Jeffrey Hamelman's Bread. This calculator counts the starter's flour and water in the totals, sometimes called true or overall hydration; some recipes instead add starter on top of the flour and water, which gives a higher real hydration than stated. Milk, eggs, butter or honey add water and fat that the calculation does not include. This page also replaces the former sourdough bread ratio calculator.
Worked examples
Classic open-crumb country loaf
One loaf with 500 g flour, 75% hydration, 20% starter, 2% salt and a 100% hydration starter.
Inputs
- Total flour500 g
- Hydration75 %
- Starter / levain20 %
- Salt2 %
- Starter hydration100 %
Result
- Flour to add450 g
- Water to add325 g
- Starter100 g
- Salt10 g
- Total dough weight885 g
- Overall hydration75 %
Mix 450 g flour and 325 g water with 100 g starter and 10 g salt for 885 g of dough. That fits a standard 9-inch (23 cm) round or oval banneton.
Two beginner loaves at 70%
A double batch with 1 kg flour at a more manageable 70% hydration.
Inputs
- Total flour1000 g
- Hydration70 %
- Starter / levain20 %
- Salt2 %
- Starter hydration100 %
Result
- Flour to add900 g
- Water to add600 g
- Starter200 g
- Salt20 g
- Total dough weight1720 g
- Overall hydration70 %
1,720 g of dough divides into two loaves of about 860 g. At 70% the dough is easier to shape, a good place to start before moving up in 2–3% steps.
High hydration with a stiff starter
450 g flour at 80% hydration, 15% stiff starter kept at 50% hydration and 2.2% salt.
Inputs
- Total flour450 g
- Hydration80 %
- Starter / levain15 %
- Salt2.2 %
- Starter hydration50 %
Result
- Flour to add405 g
- Water to add338 g
- Starter68 g
- Salt9.9 g
- Total dough weight820 g
- Overall hydration80 %
A stiff starter carries less water, so you add more water yourself: 338 g. Reserve about 20–30 g of it to add with the salt, since 80% dough can be slack.
Hydration levels and what they feel like
Percentages assume white bread flour; add a few points for whole wheat.
| Hydration | Dough | Typical use |
|---|---|---|
| 60–65% | Firm, easy to shape | Sandwich loaves, bagels |
| 68–72% | Soft but manageable | First sourdough loaves |
| 73–78% | Slack, needs folds | Country loaves with open crumb |
| 80–85% | Very wet, sticky | Ciabatta-style, experienced bakers |
| 85% and up | Batter-like | Focaccia, high-whole-grain or rye breads |
Adjusting starter and salt percentages
- Starter 10–30%: 20% is a common middle ground. Less starter slows fermentation, which suits warm kitchens or an overnight bulk; more speeds it up in a cold kitchen.
- Salt 1.8–2.2%: 2% is standard. Salt tightens gluten and slows fermentation, so very low salt gives a slack, fast-rising dough that tastes flat.
- Stiff starter (50–60%): gives a milder, less sour loaf and more water for you to add.
- Liquid starter (100–125%): the most common for home bakers; ferments faster and tastes more tangy.
- Whole grains: if 20% or more of the flour is whole wheat, raise hydration by 3–5 points to keep the same feel.
Common hydration mistakes
The most frequent error is ignoring the water in the starter. A recipe calling for 500 g flour, 375 g water and 100 g starter on top is really 550 g flour and 425 g water, or 77% hydration, not 75%. Entering your total flour here (including the starter's flour) avoids that.
The second is measuring by volume. A cup of flour can vary by 20 g or more, which changes hydration by several points; a scale that reads in 1 g steps is enough. If you are converting a cup-based recipe, use the cooking measurement converter as a first step, then weigh from then on.
How to use the Sourdough Ratio Calculator
- 1Enter the total flour for your dough in grams, including the flour that will come from the starter.
- 2Enter the target hydration (75% is a typical country loaf) and salt (usually 2%).
- 3Enter the starter percentage and your starter's own hydration, 100% if you feed equal weights of flour and water.
- 4Weigh out the flour and water to add, the starter and the salt shown, and check the total dough weight fits your banneton or tin.
Frequently asked questions
What is a good sourdough ratio for beginners?
A common starting point is 100% flour, 70% water, 20% starter and 2% salt. That is 500 g flour, 350 g water, 100 g starter and 10 g salt in a simple recipe that ignores the starter's own water.
Does sourdough hydration include the starter?
It should if you want the true figure. This calculator counts the starter's flour and water, so 75% here means the whole dough is 75% hydrated.
How much salt goes in sourdough?
About 2% of total flour weight, so 10 g for 500 g of flour. Most recipes stay between 1.8% and 2.2%.
What does 1:5:5 ratio mean for a starter?
It means 1 part starter fed with 5 parts flour and 5 parts water by weight, for example 10 g starter, 50 g flour and 50 g water. Higher feeding ratios take longer to peak.
How much dough do I need for one loaf?
Around 800–900 g of dough suits a standard 9-inch (23 cm) banneton or a 2 lb loaf tin, which is about 450–500 g of total flour at 70–75% hydration.
References
- Bread: A Baker's Book of Techniques and Recipes, Jeffrey Hamelman — Wiley
- Baker's Percentage — Bread Bakers Guild of America
About this calculator
- Built and reviewed by the Calculation Machine team · How we build and test calculators
- Last reviewed: October 24, 2026
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