500 g flour, 20% starter, 75% hydration
- Starter = 100 g
- Water ≈ 275 g
- Total dough ≈ 875 g
cooking calculator
Sourdough Starter Ratio Calculator
Calculate starter and water amounts for a target hydration and inoculation.
Results
- Starter needed (g)
- 100.00
- Water to add (g)
- 500.00
- Total dough weight (g)
- 1100.00
- Actual hydration
- 100.00%
How to use this calculator
- Enter total flour weight for your dough.
- Set starter percentage relative to flour and target hydration.
- Get starter weight, water to add, and total dough weight instantly.
Inputs explained
- Flour weight
- Total flour in the dough (excluding flour already in the starter).
- Starter % of flour
- Inoculation level relative to flour weight; higher % ferments faster.
- Target hydration %
- Total water as a percent of total flour for desired dough feel.
How it works
Starter assumed 100% hydration (half flour, half water).
We solve water needed so total hydration matches your target.
Formula
Water to add = Target hydration × (Flour + Starter/2) − Starter/2
When to use it
- Scaling a favorite loaf up or down while keeping hydration consistent.
- Testing faster or slower fermentation by adjusting starter percentage.
- Planning multi-loaf bakes with precise starter and water needs.
Tips & cautions
- This assumes a 100% hydration starter. Adjust inputs if your starter is stiffer or looser.
- Add salt separately (commonly 1.8–2.5% of flour weight).
- If adding mix-ins with water content (purees, soaked grains), reduce added water slightly.
- Does not handle non-100% hydration starters directly—manually adjust water/flour for other hydrations.
- Excludes salt and other ingredients; add them to your formula separately.
- Fermentation times still depend on temperature, flour, and starter activity.
Worked examples
300 g flour, 15% starter, 80% hydration
- Starter = 45 g
- Water ≈ 225 g
- Total dough ≈ 570 g
Deep dive
This sourdough starter ratio calculator shows how much starter and water you need for a target hydration. Enter flour weight, starter percentage, and hydration to get exact gram amounts.
Use it to scale recipes, speed up or slow down fermentation, and keep dough feel consistent. It assumes a 100% hydration starter—adjust water or flour if yours differs.
FAQs
- Does this assume a 100% hydration starter?
- Yes. If your starter is stiffer or looser, adjust flour and water manually to keep total hydration on target.
- Is salt included?
- No. Add salt separately, commonly around 2% of flour weight.
- What does starter % mean?
- It’s the weight of starter relative to flour. A higher percentage inoculates the dough more and usually ferments faster.
- How do I scale for multiple loaves?
- Enter the total flour weight for all loaves combined; outputs scale linearly.
- Can I use this for preferments like levain?
- Yes—treat the starter input as your levain build that will be mixed into the final dough.
Related calculators
Adjust for starter hydration if not 100% and account for salt separately.