Last updated: August 18, 2026
Sourdough Calculator
Creators
Dharmendra SinghReviewers
Creators
Dharmendra SinghReviewers
Quick Answer
The sourdough calculator uses baker’s percentages to convert total flour, hydration, starter percentage, starter hydration, and salt percentage into exact mixing weights. It separates the flour and water already inside the starter so you know how much fresh flour and water to add and what the final dough weight will be.
To calculate sourdough, start with total flour as 100 percent, then derive water, starter, and salt from your baker’s percentages.
Key Takeaways
- Baker’s percentages make sourdough scaling straightforward.
- Starter hydration changes how much water is already inside the culture.
- Total flour is the cleanest 100% reference point.
- Ignoring starter flour and water leads to inaccurate hydration.
- Prefermented flour helps describe fermentation intensity and timing.
Creators
Dharmendra SinghReviewers
Creators
Dharmendra SinghReviewers
Formula
Starter weight = total flour × starter%; starter flour = starter ÷ (1 + starter hydration); mix water = total water − starter water; total dough = total flour + total water + salt
Where:
- F=Total flour in final dough(g)
- h=Overall hydration(%)
- SW=Starter weight(g)
- MW=Mix water to add(g)
Worked Examples
Classic country loaf
A common 75% hydration dough with 20% 100%-hydration starter.
- 1Starter weight = 1000 × 20% = 200 g.
- 2At 100% hydration, the starter contains 100 g flour and 100 g water.
- 3Fresh flour to mix = 1000 − 100 = 900 g.
- 4Total water = 750 g, so added water = 750 − 100 = 650 g.
- 5Salt = 20 g and final dough weight = 1770 g.
Lower-hydration sandwich loaf
A more manageable dough for bakers who prefer a tidier shape and tighter crumb.
- 1Starter weight = 112.5 g.
- 2Starter contributes 56.3 g flour and 56.3 g water.
- 3Added water = 510 − 56.3 = 453.8 g.
- 4Salt = 16.5 g and final dough weight = 1276.5 g.
Large open-crumb bake
A larger batch with wetter dough and a 125%-hydration liquid starter.
- 1Starter weight = 300 g.
- 2A 125%-hydration starter contains about 133.3 g flour and 166.7 g water.
- 3Added water = 960 − 166.7 = 793.3 g.
- 4Final dough weight = 2184 g.
Introduction
Sourdough recipes become much easier to scale once you think in baker’s percentages instead of scattered ingredient lists. This sourdough calculator starts with total flour in the final dough, then allocates the right amount of water, starter, and salt according to the percentages you choose. It also separates the flour and water that are already inside your starter so you know how much fresh flour and water still need to go into the bowl. That prevents one of the most common beginner mistakes: counting the starter twice and ending up with a dough that is much wetter or drier than intended.
What this sourdough calculator solves
The calculator translates baker’s percentages into a practical mixing plan. It tells you how much starter to use, how much of that starter is already flour and water, how much fresh flour and water to add, how much salt to include, and what the final dough weight will be.
The baker’s percentage method
In baker’s math, total flour is always the 100% reference point. Hydration expresses water relative to that total flour, salt is also a percentage of total flour, and starter can be treated as a percentage of flour as well. Once the starter hydration is known, its internal flour and water can be separated exactly.
How to use the calculator
Enter the total flour you want in the final dough first. Choose the hydration level, starter percentage, starter hydration, and salt percentage that fit your style. The calculator then turns those percentages into mixing weights you can follow directly on a scale.
What hydration changes in the loaf
Higher hydration doughs are looser, stickier, and often more open-crumbed, but they are also harder to shape and score cleanly. Lower hydration doughs are easier to handle and often better for sandwich loaves. The calculator helps you see the water change immediately instead of guessing.
Why starter hydration matters
A stiff starter and a liquid starter contribute very different amounts of water even at the same total starter weight. That is why a calculator that ignores starter hydration can quietly push a dough off target. Separating the starter into flour and water keeps the overall hydration honest.
Common sourdough math mistakes
The most frequent mistake is using a starter percentage without deciding whether it is based on flour or total dough. Another is forgetting that starter already contains flour and water. Many bakers also misread hydration as a share of total dough weight rather than a percentage of flour weight.
Fermentation and food-safety notes
Healthy sourdough starter should smell pleasantly tangy rather than putrid or moldy. Keep equipment clean, refrigerate mature starter when not baking, and discard starter with visible mold or unusual discoloration. Fermentation quality matters as much as the ingredient math.
When this calculator is most useful
Use it when scaling a favorite loaf, adapting another baker’s formula to your starter hydration, planning dough weight for multiple loaves, or experimenting with wetter doughs. It is especially useful when you want consistent results across repeated bakes.
Quick Reference Card
Sourdough Quick Reference
Quick reference • Sourdough Calculator
Starter weight = flour × starter%; total water = flour × hydration%; salt = flour × salt%Valid range: Best for total flour from 300 g to several kilograms and starter hydrations of roughly 50–150%
Common Values
⚠ Watch Out
- •Do not count starter on top of a full flour-and-water formula without adjusting.
- •Very wet doughs may exceed the strength of weak flour.
- •Starter hydration must be known for accurate water math.
- •Spoiled or moldy starter should be discarded, not rescued by recipe changes.
Pro Tips
- →Use total flour as the fixed point before making any other changes.
- →Record starter hydration in your notes so future scaling stays consistent.
- →Adjust hydration in small steps when learning a new flour.
- →Use the total dough weight output to plan banneton or pan size.
FAQs
What does 100% hydration starter mean?
It means the starter contains equal weights of flour and water. For example, 200 g of 100% starter contains 100 g flour and 100 g water.
Why does the calculator ask for total flour in the final dough?
Because baker’s percentages work best when flour is the fixed 100% reference point. From there, water, salt, and starter are calculated cleanly.
Can I use this for more than one loaf?
Yes. Increase total flour until the final dough weight matches the number and size of loaves you want.
What is prefermented flour?
It is the portion of total flour that is already present in the starter before the final mix. It helps describe fermentation strength and timing.
Why can’t I just add starter on top of a full formula?
Because starter already brings flour and water. If you add it without subtracting those amounts from the main mix, hydration and dough weight drift upward.
Does higher hydration always make better bread?
Not always. Higher hydration can improve openness and gelatinization, but it also makes handling harder and may not suit every flour or shape.
How much salt is typical in sourdough?
Many sourdough formulas land around 1.8% to 2.2% salt relative to flour, though preferences vary by bread style and taste.