Baking
Sourdough Calculator
For 1,000 grams of sourdough at 75 percent hydration with 20 percent starter and 2 percent salt, mix 508 grams of flour, 367 grams of water, 113 grams of starter and 11 grams of salt. The starter counts as half flour and half water. Change any number below to build your own recipe.
Flour to add
Enter a dough weight to see the recipe.
Show the math
Sourdough hydration chart
| Hydration | Flour to add | Water to add | Starter | Salt |
|---|---|---|---|---|
| 65% | 539 g | 329 g | 120 g | 12 g |
| 70% | 523 g | 349 g | 116 g | 12 g |
| 75% | 508 g | 367 g | 113 g | 11 g |
| 80% | 495 g | 385 g | 110 g | 11 g |
| 85% | 481 g | 401 g | 107 g | 11 g |
How the calculator works
Bakers write bread recipes as percentages of the flour weight. Flour is always 100 percent, and everything else is measured against it. A dough at 75 percent hydration, 20 percent starter and 2 percent salt has, for every 100 grams of flour, 75 grams of water, 20 grams of starter and 2 grams of salt.
The calculator starts from the dough weight you want and works backward.
total flour = dough weight / (1 + hydration + salt)
Hydration and salt are written as decimals here, so 75 percent is 0.75. The starter is not in that sum, because a starter is only flour and water, and both are already counted.
Then the starter is split out. A starter fed with equal weights of flour and water, called 100 percent hydration, is half flour and half water:
- starter = total flour x starter percentage
- flour to add = total flour - half the starter
- water to add = total water - half the starter
Worked example
You want 1,000 grams of dough at 75 percent hydration with 20 percent starter and 2 percent salt.
- Total flour: 1,000 / (1 + 0.75 + 0.02) = 1,000 / 1.77 = 565 grams.
- Total water: 565 x 0.75 = 424 grams.
- Starter: 565 x 0.20 = 113 grams, which holds 56.5 grams of flour and 56.5 grams of water.
- Flour to add: 565 - 56.5 = 508 grams.
- Water to add: 424 - 56.5 = 367 grams.
- Salt: 565 x 0.02 = 11 grams.
Check: 508 + 367 + 113 + 11 = 999 grams, which is 1,000 after rounding.
Why the starter has to be counted
It is tempting to treat starter as an extra and work out hydration from the flour and water you weigh out. That gives the wrong number.
Take 500 grams of flour, 350 grams of water and 100 grams of starter. Without the starter that looks like 350 / 500 = 70 percent. With it, the dough holds 550 grams of flour and 400 grams of water, and 400 / 550 = 73 percent. The more starter a recipe uses, the bigger that gap gets.
This is also why two recipes that both claim “75 percent hydration” can feel different in the hands. One may be counting the starter and the other not.
What hydration changes
Hydration is the number that most affects how dough handles.
- Around 65 percent. Firm dough that holds its shape and is easy to score. A good place to start.
- Around 75 percent. Softer and stickier. It needs folding to build strength.
- 80 percent and above. Loose, wet dough that spreads unless it is handled with practice.
The chart above shows how the flour and water shift across that range for the same 1,000 grams of dough. The total weight does not change. Water goes up and flour comes down.
Flours do not all take up water the same way. Whole wheat and rye absorb more than white bread flour, so a dough that is mostly whole grain can take a higher hydration and still feel manageable.
If your starter is not 100 percent hydration
The calculator assumes a starter fed with equal weights of flour and water, which is what most home bakers keep. A stiff starter contains less water and a liquid one more.
If yours is different, the totals shift slightly. For a small amount of starter the difference is a few grams of water. Mix the dough as calculated, then add a splash of water or a dusting of flour by feel.
Tips and common mistakes
Hold back a little water. Mix with about 20 grams less than the recipe says, and work the rest in once the dough has come together. It is easier to add water than to take it out.
Change one number at a time. If you raise the hydration and switch flours in the same bake, you will not know which change made the difference.
Write down what you did. The percentages make it easy to repeat a good loaf at any size: keep the percentages and change only the dough weight.
Scale by dough weight, not by flour. If your banneton holds 900 grams, enter 900 and let the calculator work out the rest.
Frequently asked questions
What does 75 percent hydration mean?
It means the dough contains 75 grams of water for every 100 grams of flour. Both figures count the flour and water inside the starter as well as what you add yourself.
How much starter should I use?
Many recipes use starter at about 20 percent of the flour weight. Less starter gives a slower rise and more starter a faster one, so the right amount depends on your schedule and your kitchen temperature.
How do I calculate hydration with a starter?
Add half the starter weight to your flour and half to your water, then divide total water by total flour. With 500 grams of flour, 350 grams of water and 100 grams of starter: 400 / 550 = 73 percent.
How much salt goes in sourdough?
About 2 percent of the total flour weight is the usual amount. For a dough with 500 grams of flour in total, that is 10 grams of salt.
How much dough do I need for one loaf?
That depends on your banneton or tin. Enter the dough weight your basket is sold for, or weigh the dough from a recipe you already like and use that number.