How to use the sourdough calculator
- Choose how much bread. Set the number of loaves and the dough weight for each. 900 g makes a standard loaf baked in a Dutch oven.
- Set your hydration. This is how wet the dough is. New to sourdough? Start at 68–72% – it's much easier to shape.
- Set your starter percentage. 20% works at a normal room temperature of about 24 °C / 75 °F.
- Weigh everything. Use the grams shown – a digital scale is far more accurate than cups.
Tap Share link to save the numbers: the link reopens the calculator with your exact settings.
What is sourdough hydration?
Hydration is the weight of water divided by the weight of flour. 750 g of water with 1,000 g of flour is 75% hydration. Higher hydration gives a more open, glossy crumb but a stickier dough; lower hydration gives a tighter crumb and a dough that holds its shape.
| Hydration | Dough feel | Good for |
|---|---|---|
| 60–65% | Firm, easy to shape | Sandwich loaves, rolls, beginners |
| 66–72% | Soft but manageable | Your first boules and batards |
| 73–78% | Soft, slightly sticky | Classic open country loaf |
| 79–85%+ | Very wet, slack | Wide-open crumb, experienced bakers |
Whole wheat, rye and freshly milled flour drink more water. With 50% whole wheat, a dough at 80% feels about like a white dough at 72–75%.
Why starter changes your hydration
A 100% hydration starter is half flour, half water. So 100 g of starter adds 50 g of flour and 50 g of water to your dough. Most simple recipes ignore this, which is why a recipe that says "70%" is often really closer to 73%.
With true hydration switched on (the default), this calculator counts that hidden flour and water, so the hydration you type is the hydration you get. Switch it off to match recipes that use the simple method.
A simple sourdough method
- Feed your starter 4–12 hours ahead so it's bubbly and at peak when you mix. Our starter feeding calculator tells you the ratio to use.
- Mix flour, most of the water and the starter until no dry flour remains. Rest 30–45 minutes, then add salt and the remaining water and squeeze it through the dough.
- Bulk ferment 4–7 hours at room temperature with 3–4 sets of stretch and folds in the first two hours. It's done when the dough has grown 50–75% and looks airy. See the bulk fermentation calculator for your temperature.
- Shape into a tight round or oval and place it seam-side up in a floured basket.
- Cold proof in the fridge for 8–16 hours.
- Bake in a preheated Dutch oven at 250 °C / 480 °F with the lid on for 20 minutes, then lid off at 230 °C / 450 °F for 20–25 minutes until deep brown.
Want the whole bake timed around your day? Use the sourdough schedule planner.
Frequently asked questions
What is a good hydration for sourdough bread?
Most beginners do well between 65% and 72%. Open, airy loaves usually sit at 75–80%, but wetter dough is harder to shape. Whole wheat and rye absorb more water, so they can take 5–10% more than white flour at the same feel.
How much starter should I use in sourdough?
Most recipes use 10–25% starter relative to flour. 20% is a reliable default at around 24 °C / 75 °F. Use less (5–10%) in a warm kitchen or for long, slow fermentation, and more (25–30%) when your kitchen is cold.
What does "count starter in hydration" mean?
Your starter is half flour and half water (at 100% hydration). When this is on, the calculator counts that flour and water too, so 75% really means 75% of all the flour in the dough. This is called true or total hydration and it's what bakers compare between recipes.
How much salt goes in sourdough?
2% of the flour weight is the standard – 10 g of salt per 500 g of flour. Anywhere from 1.8% to 2.2% works; go below 1.5% and the bread tastes flat and ferments faster.
How much dough do I need for one loaf?
A typical home boule or batard made in a Dutch oven weighs 850–950 g of dough. Use about 700 g for a small loaf and 1,100–1,200 g for a large one or a 5-quart Dutch oven.