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.

Frequently Asked Questions

Does my starter hydration affect the calculation?

Yes, and most calculators ignore this. If you use a 100% hydration starter (equal weights flour and water), half of your starter weight is flour and half is water. For 100g of starter, that's 50g flour and 50g water hidden inside it. This calculator includes those in your true totals, which matters when comparing recipes or troubleshooting dough that feels wetter or drier than expected.

What hydration should a beginner sourdough baker use?

Start at 68–70%. It is soft enough to develop good gluten through stretch and folds, but firm enough to shape without frustration. Once you can consistently produce a good loaf at this hydration, move up to 72–74% and notice what changes. Jumping straight to 80% is one of the most common reasons beginners give up on sourdough.

Why does my dough feel wetter than the hydration suggests?

Several reasons: your flour absorbs water differently than the recipe writer's flour (whole grain and lower-protein flours absorb more slowly), your kitchen temperature affects how the gluten behaves, and newly mixed dough always feels wetter than it will after autolyse and the first set of stretch and folds. Give it 30–45 minutes before deciding it needs more flour.

Should I use the same hydration for whole wheat as for white flour?

No — whole wheat absorbs significantly more water because the bran particles soak it up slowly. If you switch from white to whole wheat at the same hydration, your dough will feel firmer at first then become wetter as the bran absorbs moisture over time. As a starting point, add 5% extra hydration for every 20% whole wheat in your blend.

What is the difference between hydration and inoculation?

Hydration measures the ratio of water to flour. Inoculation measures the ratio of starter to flour. They are independent variables — you can have high hydration with low inoculation or low hydration with high inoculation. Both affect your results, but in different ways. Hydration controls dough feel and crumb structure. Inoculation controls fermentation speed. Use our Bake Planner to dial in both at once.

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.