Sourdough hydration calculator, starter counted.
Sourdough hydration is total water ÷ total flour × 100, with your starter counted toward both. Lock what you know — flour, water, starter, hydration or dough weight — and LoafMath solves the rest.
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- Bi-directional — lock any three values, solve the other two.
- True hydration — the starter’s flour + water are always counted.
- Shows the math — no black box; copy, print or save your recipe.
- No sign-up, works offline, your numbers never leave your browser.
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How do you calculate sourdough hydration?
Baker’s percentage is the language every bread recipe is written in. It expresses each ingredient as a percentage of the total flour weight, and flour is always 100%. Water at 75% means 75 g of water for every 100 g of flour; salt at 2% means 2 g per 100 g of flour. Because everything is relative to flour, you can scale a formula to one loaf or ten and the dough behaves exactly the same.
Hydration is simply total water ÷ total flour × 100. The mistake almost every basic calculator makes is treating your sourdough starter as a single mystery ingredient. It isn’t — a starter is flour and water that have already been mixed. At 100% hydration it’s half of each, so a 150 g starter is quietly adding 75 g of flour and 75 g of water to your dough. Ignore that and the hydration on your screen won’t match the dough in your hands.
The worked example LoafMath starts you with
Take 500 g of added flour, a 150 g starter at 100% hydration, a 75% target and 2% salt. The starter splits into 75 g flour + 75 g water. So your totals are 575 g flour and a 431 g water target — but 75 g of that water is already in the starter, so you only add 356 g of water and 11.5 g of salt. Total dough ≈ 1,018 g — two respectable loaves. That’s the recipe pre-loaded above; change any locked value and watch the rest re-solve.
Already know the hydration you want? Each level has its own page with the dough behaviour, flour choice and handling that go with it — 65%, 70%, 75%, 80% and 85%.
Sourdough hydration chart: water for one loaf
How much water to add for each hydration, with 500 g of flour, 100 g of ripe 100% hydration starter and 2% salt. The starter’s own 50 g of water is already counted, so these are the grams you pour in.
| Hydration | Water to add | Total dough |
|---|---|---|
| 60% | 280 g | 891 g |
| 65% | 308 g | 919 g |
| 70% | 335 g | 946 g |
| 75% | 363 g | 974 g |
| 80% | 390 g | 1001 g |
| 85% | 418 g | 1029 g |
| 90% | 445 g | 1056 g |
Leave the starter out of the sum and the numbers drift. Pour 75% of the 500 g of flour as water (375 g) and the dough actually ends up at 77.3% hydration, because the starter added 50 g of water and 50 g of flour on top.
Sourdough hydration FAQ
How do I calculate my sourdough hydration?
Hydration is total water ÷ total flour × 100. The catch: your starter is itself flour and water, so it adds to both totals. A 100% starter is half flour, half water — a 150 g starter contributes 75 g flour and 75 g water. LoafMath adds those in automatically, so the hydration you see is the true hydration of the dough, not just the water you poured in.
Is 70% hydration high for sourdough?
70% is a comfortable middle for a home baker — wet enough for an open-ish crumb, dry enough to shape without a fight. Below ~68% is easier to handle and gives a tighter crumb; 75–80%+ gives a more open crumb but demands better technique and stronger flour. Beginners usually do best starting around 68–72%.
What is a good hydration ratio for sourdough bread?
For a classic hearth loaf, 72–78% is the sweet spot with bread or high-protein flour. Enriched or sandwich loaves sit lower (60–68%); ciabatta and focaccia go higher (80%+). Whole-grain flours drink more water, so add 3–5% for every big jump in whole-grain content.
Is 60% hydration too low for sourdough?
Not at all — it just makes a firmer dough with a tighter, more uniform crumb. Bagels, pretzels and some sandwich loaves live around 55–65%. It’s a great hydration to learn shaping on because the dough holds its shape. You won’t get big open holes, and that’s by design.
How do you calculate baker’s percentage?
Every ingredient is expressed as a percentage of the total flour weight, and flour is always 100%. So water ÷ flour × 100 is your hydration %, salt ÷ flour × 100 is your salt %, and so on. Because everything is relative to flour, you can scale a recipe up or down and the ratios — and the result — stay identical.
How do I work out my starter’s hydration?
If you feed it the same way each time, divide the water you feed by the flour you feed and multiply by 100. Equal weights, such as 50 g flour and 50 g water, make a 100% starter; 50 g flour and 25 g water make a stiff 50% starter. Enter that number as the starter hydration in the calculator and it splits your starter into flour and water for you.
Can I use the hydration calculator with cups?
Yes. Switch the units to cups and the calculator converts every amount, but treat cups as approximate: it assumes about 120 g of flour per cup (King Arthur Baking’s weight chart) and about 236 g of water. How you scoop flour changes what a cup weighs, so weigh in grams when the hydration matters.