Sourdough Hydration Calculator

How to use this calculator

This calculator turns two practical choices into a usable bread formula: how much dough you want to make, and how wet you want it to be. Type in the total dough weight in grams, move the hydration slider between 50% and 100%, and it shows the flour and water needed to reach that hydration.

The result treats the dough as flour plus water — the cleanest way to understand hydration before salt, starter, oil, seeds, or grains enter the picture. Once you know the base split, you can build a full formula around it.

Worked examples

Three quick cases that show how hydration, flour, and starter interact. Hydration is always water ÷ flour × 100, and any 100% starter you add counts as equal flour and water.

What sourdough hydration means

Hydration is a baker's percentage. Instead of describing water as a percentage of the whole dough, bakers describe water as a percentage of flour weight. Flour is always 100%. If a dough has 500g of flour and 350g of water, hydration is 70% — because 350 is 70% of 500.

This is useful because flour is the anchor of a bread formula. Salt might be 2%, starter 15–25%, water 65–85% — but every number refers back to flour. Once you read baker's percentages, recipes become much easier to scale.

The formula behind the calculator

Hydration is water divided by flour, times 100. When you know the total dough weight, flour is the total divided by one plus the hydration expressed as a decimal, and water is the remaining weight.

The ratio bar makes it visible: at lower hydration, flour takes up more of the bar; at higher hydration, the water section grows.

Choosing the right hydration level

There is no single best hydration for every loaf. The right number depends on your flour, temperature, shaping confidence, schedule, and the style of bread you want. Lower-hydration doughs are stronger, easier to handle, and more predictable.

For a first loaf, 65–70% is a friendly range. Around 72–78% is a common artisan zone, especially with bread flour. Above 80% you're in high-hydration territory: great for open crumb, focaccia, and ciabatta, but much less forgiving during shaping.

How flour changes hydration

Flour absorption matters as much as the percentage itself. Strong bread flour usually takes more water than soft all-purpose. Whole wheat, spelt, and rye bring bran, germ, and different starch behaviour, so they often need more water or a longer rest.

Hold back 20–30g of water if you're unsure. Mix the dough, judge the feel after a short rest, and add the reserved water only if the flour can take it.

Accounting for starter in a full dough

Sourdough starter contains flour and water, so it contributes to the final hydration. A 100% hydration starter is equal parts flour and water by weight — add 100g of it and you're adding 50g of flour and 50g of water.

If your target needs 500g flour and 375g water, and you add 100g of 100% starter, the starter already brings 50g flour and 50g water — so your final mix adds 450g fresh flour and 325g fresh water.

What hydration does to dough handling

Hydration changes the feel of dough from the first mix to the final score. At lower hydration, dough resists stretching and can be shaped with dry hands. At moderate hydration, it becomes extensible and benefits from stretch and folds or coil folds.

If dough feels unworkable, the answer isn't always less water. Sometimes it needs more gluten development, more rest, or less fermentation. Use the calculator to choose the formula, then let dough feel, rise, bubbles, and timing guide the ferment.