Sourdough Hydration Calculator

What is sourdough hydration?

Hydration is the ratio of water to flour in your dough, expressed as a percentage. A 75% hydration dough contains 75 grams of water for every 100 grams of flour. It's the single most important number in bread baking because it determines the texture of the crumb, the crust, how the dough handles, and how forgiving the recipe is.

In sourdough, this is complicated slightly by the starter.which is itself a mixture of flour and water. A proper hydration calculation (and this calculator) accounts for the flour and water inside the starter, so the target you set is the true total hydration of the final dough. Most online recipes get this wrong.

Using the calculator

Enter a value in any field and the results update instantly. The five inputs are:

Flour weight.the main dough flour in grams (not counting starter). Target hydration.your desired total hydration percentage. Starter hydration.the water-to-flour ratio of your starter; 100% is standard for a 1:1:1 feed. Starter as % of flour.how much starter relative to your main flour; 20% is typical. Salt.as a percentage of total flour; 1.8–2.2% is the standard range.

The results section shows you exactly how much water, starter, and salt to weigh out, plus a full breakdown of what's happening inside the starter so you can cross-check the totals.

Click Share result to copy a link that pre-fills all five inputs.useful for sharing a recipe on Reddit or sending settings to a friend.

How baker's math works

Baker's math (also called baker's percentage) expresses every ingredient as a percentage of flour. Flour is always 100%. If you use 500g flour, 375g water, 100g starter, and 11g salt, that's 75% water, 20% starter, and about 2% salt.

This system is scale-independent. A 75% hydration recipe works the same whether you're making one loaf or fifty. It also lets you think about the dough without worrying about batch size. "75% hydration, 20% starter, 2% salt" describes the dough's character completely.

This calculator does the conversion for you.enter real-world gram amounts and your target percentages, and it produces the exact weights to put on your scale.

What the hydration levels mean

Below 65%.stiff dough. Dense, easy to shape, tighter crumb. Bagels and some sandwich breads live here. Good for beginners because the dough is forgiving during shaping and doesn't spread on the counter.

65–72%.moderate hydration. The classic sourdough window. You get an open crumb without fighting the dough. Most “country loaf” recipes land at 68–72%. Workable by hand, shapes well with a bench knife and a light touch.

72–80%.slack / high hydration. This is where things get interesting. Beautiful, irregular open crumb, thin crispy crust, but the dough is wet and sticky. You need strong gluten development (long autolyse, coil folds or stretch-and-folds) and confident, gentle shaping.

Above 80%.very high hydration. Ciabatta, focaccia, and pan loaves. Extremely wet.you're not shaping this freeform on a bench. Wet hands, oiled containers, and bannetons are essential. The crumb can be spectacularly open.

How starter hydration affects your dough

Most bakers maintain a 100% hydration starter.equal parts flour and water by weight (a 1:1:1 feed). At 100%, every gram of starter contributes half a gram of flour and half a gram of water to the dough.

A stiffer starter (say 60–80%) contributes more flour and less water, so you'll need to add more water to hit your target hydration. A looser starter (120%+) contributes more water, so you'll reduce the added water. This calculator handles the arithmetic automatically.just enter your starter's actual hydration and it adjusts.

If you're not sure of your starter's hydration: if you feed equal weights of flour and water (e.g. 50g flour + 50g water + 50g starter), it's 100%. If you feed by volume (1 cup flour + ½ cup water), it's roughly 60–65%.flour is denser than water by volume.

Temperature also plays a role in how much starter you need. In a cold kitchen (below 18°C / 65°F), fermentation is sluggish.bump starter percentage toward the higher end of the range (25–30%). In a warm kitchen (above 24°C / 75°F), activity is faster and you can reduce it to 15–18% to avoid over-proofing. The calculator's default of 20% is a good baseline for a typical room-temperature bake.

Hydration and fermentation time

Hydration and starter percentage set the dough's character.but bulk fermentation time is the other half of the equation. A higher-hydration dough with more starter ferments faster; a stiff, low-starter dough can take twice as long at the same temperature. Getting those timings right is what separates a reliably open crumb from a dense one.

Temperature-adjusted bulk fermentation timing.including guidance on when the dough is ready to shape.is what the Fermentation Planner covers. It's next on the build list.

Tips for high-hydration sourdough

Autolyse first. Mix flour and water (no starter, no salt) and let it sit 30–60 minutes. The flour hydrates fully and gluten starts forming before you even begin working the dough. This makes high-hydration doughs dramatically easier to handle.

Wet your hands, not the dough. When doing stretch-and-folds or coil folds, dip your hands in water. Adding dry flour to a wet dough changes the hydration; wet hands don't.

Use a banneton. A floured banneton (proofing basket) gives slack dough structure during the final proof. Without one, high-hydration dough flattens out and you lose oven spring.

Score deeply. Wet doughs expand fast in a hot oven. A deep, confident score (¼ to ½ inch) gives the steam somewhere to go and controls the direction of the rise.

Frequently asked questions

How much starter should I add to 500g of flour?

At the standard 20% rate, you need 100g of starter for 500g of flour. In a cold kitchen (below 18°C / 65°F), you can go up to 25–30% to compensate for slower fermentation. In a warm kitchen (above 24°C / 75°F), 15–18% is plenty.

What is a good hydration for beginner sourdough?

65–70% is the sweet spot for beginners. The dough is workable, holds its shape during shaping, and still produces an open crumb. Most country loaf recipes land in this range. Save 75%+ for when you're comfortable with stretch-and-fold technique.

Does this calculator account for the flour and water inside the starter?

Yes. This is one of the key things that sets this calculator apart. It extracts the flour and water from your starter and counts them toward the total dough hydration. So when you set 75% hydration, you actually hit 75%.not a rough approximation.

What is sourdough starter hydration?

Starter hydration is the ratio of water to flour in your starter, expressed as a percentage. A 100% hydration starter is fed equal weights of flour and water.the most common approach. A 75% starter is stiffer (more flour relative to water), and a 125% starter is looser. Changing this affects how much water your starter contributes to the dough, which this calculator adjusts for automatically.

How do I calculate total sourdough hydration?

Total hydration = total water ÷ total flour × 100, where both totals include the flour and water inside your starter. For example: 500g main flour + 50g starter flour (from a 100% hydration 100g starter) = 550g total flour. 375g added water + 50g starter water = 425g total water. Hydration = 425 ÷ 550 × 100 = 77.3%.

What percentage of salt should I use for sourdough?

1.8–2.2% of total flour is the standard range. This calculator defaults to 2%. Salt tightens gluten structure, slows fermentation slightly, and affects flavour. Going below 1.5% makes the dough slack and bland. Above 2.5% can inhibit your starter.