Sourdough Calculator (Hydration & Starter)
Dial in hydration and starter for a perfect sourdough loaf.
- Flour to add
- 450 g
- Water to add
- 325 g
- Starter (20%)
- 100 g
- Salt (2%)
- 10 g
- Total flour (75% hydration)
- 500 g
- Total dough
- 885 g
- Amounts assume your starter is at the hydration shown (default 100% — equal flour and water).
- Higher hydration gives a more open crumb but a stickier, harder-to-shape dough.
- Hold back a little water at first and add it during mixing if the dough can take it.
Saved setups
Save your settings to reuse them later. They’re stored only on this device — nothing is uploaded.
What is the Sourdough Hydration Calculator?
The sourdough calculator builds a loaf from baker’s percentages and — crucially — accounts for the flour and water already in your starter, so your final hydration is correct. Set your total flour, target hydration, the amount of starter and the salt, and it tells you exactly how much extra flour and water to add. It’s built for sourdough bakers who want repeatable, well-hydrated loaves without doing the levain maths by hand.
How to use the Sourdough Hydration Calculator
- 1 Enter your total flour weight and target hydration.
- 2 Set how much starter you’re using as a percentage of flour.
- 3 Adjust salt and starter hydration under More options if needed.
- 4 Add the flour and water amounts the calculator gives you.
Frequently asked questions
Does the starter count towards hydration? +
Yes — a 100% hydration starter is half flour and half water, and this calculator subtracts both from the flour and water you add, so your stated hydration is the true final hydration.
What hydration should sourdough be? +
Most everyday loaves sit around 70–78%. Higher hydration gives a more open crumb but a stickier dough that’s harder to shape.
How accurate are the results? +
The figures come from standard, tested references (USDA FoodData Central and King Arthur Baking) and are excellent starting points. Ovens, ingredients and equipment vary, so treat the numbers as a reliable guide and adjust to taste and doneness.
Is this calculator free, and does it send my data anywhere? +
Yes — it’s completely free and runs entirely in your browser. Nothing you type is uploaded or stored on a server; the maths happens on your device, even offline once the page has loaded.