Sourdough Calculator
Work out water, starter and salt for a sourdough loaf from flour weight and hydration.
Formula and sources updated · Data sources · 1View algorithm, constants and default inputs (JSON)
About this calculator
Set flour weight and baker’s percentages to calculate added water, starter and salt. The hydration shown is water added as a percentage of flour; starter is weighed separately, so final dough hydration depends on the starter’s own flour and water content.
Worked example
calculated with the default values below
Flour 500 g · Added water (% of flour) 75 % · Starter 20 % · Salt 2 % Water 375.0 g · Starter 100.0 g · Salt 10.0 g · Total dough 985 g · Loaves at 800 g 1.23
Method and assumptions
T = F × (1 + h÷100 + s÷100 + a÷100) Baker's percentages: water, starter and salt are all relative to flour F. Number of 800 g loaves = T ÷ 800. Set flour weight and baker’s percentages to calculate added water, starter and salt. The hydration shown is water added as a percentage of flour; starter is weighed separately, so final dough hydration depends on the starter’s own flour and water content. The references explain definitions and methods; any extra preset must be checked against the assumptions on this page.
Data sources
The references explain definitions and methods; any extra preset must be checked against the assumptions on this page.
Disclaimer
These calculators give general cooking guidance. Ingredient density, oven calibration, altitude and equipment all vary, and safe minimum internal temperatures always take precedence over timings. Follow the food-safety advice issued by your national authority.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
T = F × (1 + h÷100 + s÷100 + a÷100)
- F
- Flour (g)
- h
- Hydration (%)
- s
- Starter (%)
- a
- Salt (%)
Baker's percentages: water, starter and salt are all relative to flour F. Number of 800 g loaves = T ÷ 800.
Frequently asked questions
Why does the starter count as part of the dough weight?
The tool treats starter, water and salt all as percentages of the 500 g flour, so at 20% starter and 75% hydration a 500 g batch uses 100 g starter and 375 g water plus 10 g salt, totalling 985 g. Dividing by an 800 g loaf target gives about 1.2 loaves. Because starter is itself half flour and half water, it quietly raises both the flour and liquid totals beyond what you added separately, which the hydration tool untangles separately.
Which inputs and limits apply to Sourdough Calculator?
Use the units shown beside each field. These are form limits, not recommended settings. Flour: 0–100,000 g; Added water (% of flour): 0–120 %; Starter: 0–100 %; Salt: 0–5 % T = F × (1 + h÷100 + s÷100 + a÷100) Baker's percentages: water, starter and salt are all relative to flour F. Number of 800 g loaves = T ÷ 800. Set flour weight and baker’s percentages to calculate added water, starter and salt. The hydration shown is water added as a percentage of flour; starter is weighed separately, so final dough hydration depends on the starter’s own flour and water content. The references explain definitions and methods; any extra preset must be checked against the assumptions on this page.
What is a complete worked example for Flour = 500 g; Added water (% of flour) = 75 %?
Inputs: Flour = 500 g; Added water (% of flour) = 75 %; Starter = 20 %; Salt = 2 %. Calculation: T = F × (1 + h÷100 + s÷100 + a÷100). Results: Water = 375.0 g; Starter = 100.0 g; Salt = 10.0 g; Total dough = 985 g; Loaves at 800 g = 1.23.