Sourdough Calculator

Sourdough bread is made from just flour, water, salt, and a "starter" — a live culture of fermented flour and water that makes the dough rise naturally, instead of using packaged yeast. How much water you use relative to flour (called hydration) is the single biggest thing that determines how the dough behaves and how the bread turns out: less water makes a firmer dough that's easy to handle but a denser loaf, while more water makes a stickier, harder-to-shape dough that bakes up lighter and airier inside.

Recipes usually give you a target hydration to aim for, but working it out by hand is fiddlier than it sounds — your starter is itself made of flour and water, so its weight has to be split out and added to your totals before you get your true hydration, not just what you poured in directly. That's the part this calculator does for you: enter what you have, and it instantly gives you your real hydration and how much salt to add, so you know exactly where you stand before you start mixing.

Flour is the base of every measurement — Water and Starter are the direct grams you type in above. Because your starter already contains its own flour and water (this calculator assumes a 100% hydration starter, equal parts flour and water), half its weight is added to the flour total and half to the water total before working out your true Hydration — not just the water and flour you typed in directly. Salt is calculated automatically at 2% of the flour you enter, a standard starting point for most sourdough loaves.