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Sourdough hydration calculator
Starter holds flour and water too. This calculator counts both. The hydration it shows is the real figure for the dough.
Enter weights in grams. Starter hydration is the water in the starter as a percent of its flour.
How the hydration is worked out
A starter at 100 percent hydration is half flour and half water by weight. At any hydration H the flour in the starter is its weight divided by 1 plus H over 100. The rest is water.
Add the starter flour to the flour and the starter water to the water. True hydration is total water divided by total flour.
Baker's percentages state every ingredient as a percent of total flour, which is 100 percent.
Example
A loaf uses 500 g of flour, 350 g of water and 100 g of starter at 100 percent hydration.
The starter holds 50 g of flour and 50 g of water. Total flour is 550 g and total water is 400 g.
400 divided by 550 is 72.7 percent hydration.
Questions about this page
What hydration should a beginner use?
Lower is easier to handle. Many bakers start around 65 to 75 percent.
Does whole wheat need more water?
Usually yes. Whole grain flour absorbs more.
Why does my recipe give a different number?
Some recipes leave the starter out. This page includes it.
What if my starter is not 100 percent hydration?
Enter its hydration. A stiffer starter holds more flour per gram.