Sourdough & Bread Hydration Calculator
Work out the real hydration of your dough, counting the flour and water inside the starter and any milk or eggs, or build a sourdough recipe from a target dough weight.
| Ingredient | Grams | Baker's % |
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Hydration guide
| Bread | Typical hydration | Dough feel |
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How to use the Sourdough & Bread Hydration Calculator
- Choose a mode: Find my hydration for an existing recipe, or Build a recipe from scratch.
- To find hydration, enter the flour, water, starter amount and starter hydration. Add other flours or liquids such as milk with the + buttons.
- To build a recipe, set the number of loaves, dough per loaf, hydration, salt, starter percentage and starter hydration.
- Plan the levain with a build ratio such as 1:5:5 and a little extra to keep back.
- Read the results and compare them with the hydration guide, then press Copy to save them.
How to calculate true dough hydration
Hydration is total water ÷ total flour × 100. The catch with sourdough is that the starter contains both. For a starter at hydration h (as a decimal):
- Flour in starter = starter weight ÷ (1 + h)
- Water in starter = starter weight − flour in starter
Example: 450 g bread flour, 50 g whole wheat, 350 g water, 100 g starter at 100% and 10 g salt. The starter holds 50 g flour and 50 g water, so total flour = 550 g and total water = 400 g. True hydration = 400 ÷ 550 = 72.7%. Ignoring the starter you would get 350 ÷ 500 = 70%. Salt is 10 ÷ 550 = 1.8% and the inoculation is 100 ÷ 500 = 20% of the added flour.
A stiff 50% starter of 100 g holds 66.7 g flour and 33.3 g water instead, so the same recipe would be 383.3 ÷ 566.7 = 67.6%.
Building a recipe from percentages
When every percentage is relative to the total flour, the dough weight is flour × (1 + hydration + salt). So total flour = dough weight ÷ (1 + hydration + salt). For a 1,000 g loaf at 75% hydration and 2% salt: 1,000 ÷ 1.77 = 565 g flour, 424 g water and 11 g salt. With 20% starter (113 g at 100% hydration, holding 56.5 g of each), you add 508 g flour and 367 g water to the starter.
Levain build ratios
A levain is built from a spoonful of mature starter (the seed) plus fresh flour and water, written seed : flour : water. More fresh food relative to the seed means a slower, often milder levain. Typical timings at about 24 °C (75 °F):
| Ratio | Seed for 100 g levain | Usually ripe in | Good for |
|---|---|---|---|
| 1:1:1 | 33 g | 4–6 h | Same-day baking, very active starter |
| 1:2:2 | 20 g | 5–8 h | Morning build, afternoon mix |
| 1:5:5 | 9 g | 8–10 h | Overnight build before a morning mix |
| 1:10:10 | 5 g | 10–14 h | Warm kitchens or long overnight builds |
Use the levain at its peak: domed, bubbly and roughly doubled. Colder rooms slow it down considerably, warmer ones speed it up.
Tips for working with hydration
- Whole-grain flours absorb more water: for every 10% of whole wheat in the flour, many bakers add 2–5% more water.
- Hold back 5–10% of the water at the start and add it during mixing (bassinage) so you can stop if the dough gets too slack.
- Salt is normally 1.8–2.2% of total flour; it tightens dough and slows fermentation.
- Higher hydration ferments faster and needs more strength-building folds and a well-floured banneton.
Frequently asked questions
What is dough hydration?
Hydration is the weight of water divided by the weight of flour, as a percentage. 700 g of water with 1,000 g of flour is 70% hydration. Higher hydration usually means a stickier dough and a more open crumb.
Why does the starter change the hydration?
A starter is part flour and part water. 100 g of a 100% hydration starter adds 50 g of flour and 50 g of water. A recipe with 500 g flour, 350 g water and 100 g starter is therefore 400 ÷ 550 = 72.7% hydration, not 70%.
What is starter hydration?
It is the water-to-flour ratio of the starter itself. Equal weights of flour and water make a 100% (liquid) starter; a stiff starter is often 50–65%.
What is inoculation or levain percentage?
It is how much starter you use relative to the flour. Bakers quote it either against the added flour or the total flour; this calculator shows both. 15–25% is common for an overnight bulk; lower amounts slow fermentation down.
Does milk count as water in hydration?
Partly. Whole milk is about 87% water, eggs about 75% and butter about 16%, so only that share counts towards hydration. The calculator uses these typical values, which you can adjust.
Why does my dough feel wetter than its hydration suggests?
Flour absorbs water differently. Whole-grain, high-protein and freshly milled flours absorb more, so the same hydration feels stiffer; weak all-purpose or low-protein flour feels wetter. Start lower with a new flour and add water gradually.