Sourdough Hydration Calculator
Hydration is the single number that changes how your dough feels, shapes, and bakes. Use this calculator to get your true hydration percentage using flour, water, and starter weight, including flour and water hidden in your starter.
How to Use This Calculator
- Enter main flour and main water first.
- Add your starter amount and starter hydration.
- Use the true hydration plus total flour/water cards to compare recipes accurately.
[sc_faq source=”hydration-faq.json” title=”Frequently Asked Questions”]
What Is Sourdough Hydration?
Hydration in sourdough refers to the ratio of water to flour in your dough, expressed as a percentage. A dough made with 400g flour and 300g water has 75% hydration. But that single number conceals a lot — because your sourdough starter also contains flour and water. True hydration accounts for all the flour and water in the recipe, including what’s in your starter.
This calculator gives you true hydration. That matters because two recipes that both say “75% hydration” can produce very different doughs if one uses a 100% hydration starter and the other uses a stiff levain. The calculator removes that ambiguity entirely.
How Hydration Affects Your Dough
Lower hydration doughs (65–70%) are stiffer, easier to shape, and produce a tighter, more even crumb. They’re more forgiving for beginners. Higher hydration doughs (75–85%) produce a more open, irregular crumb but require stronger gluten development and more skill to handle. If your dough is spreading sideways, sticking to everything, or tearing during shaping, hydration is often the first variable to adjust.
Different flours also absorb water differently. Bread flour absorbs significantly more than all-purpose, which is why you can’t simply swap flours without adjusting water. Whole wheat and rye absorb even more due to bran content. Use this calculator any time you change flour types to recalculate your true hydration.
As a general guide: 65–70% is ideal for beginners and sandwich loaves, 72–76% works well for most home bakers targeting an open crumb, and 78%+ is for experienced bakers who have mastered gluten development and shaping technique.
When to Use This Calculator
Use it before every bake to confirm your recipe’s true hydration. Use it when adapting a recipe to a different flour — recalculate with the new flour’s absorption in mind. Use it when troubleshooting: if your loaf came out gummy or sticky, knowing the true hydration tells you whether the dough was simply too wet for your skill level or the conditions in your kitchen.
It’s also useful for scaling recipes. When you double or halve a recipe, the ratios stay the same — but it’s easy to make errors when scaling starter amounts. Running the scaled numbers through this calculator takes 10 seconds and confirms everything is correct before you mix.