The Sourdough Hydration Calculator from ToolForever turns baker’s percentages into exact gram measurements for any sourdough bread recipe. Enter your total flour weight, target hydration, salt percentage, and sourdough starter amount — and the calculator instantly returns precise weights for flour, water, salt, and active levain, accounting for the flour and water already contained in your starter.
Whether you are scaling a country loaf, dialing in a wetter ciabatta dough, or designing your own artisan formula, this free baker’s percentage calculator replaces messy mental math with clean, repeatable numbers.
Sourdough baking lives or dies by hydration. Get the water-to-flour ratio right and you get an open crumb, blistered crust, and a loaf that rises properly. Get it wrong and the dough tears during shaping, the crumb becomes gummy, or the bread sits flat in the basket. This calculator is built to remove that variable from your bake.
Why Use a Sourdough Hydration Calculator
Sourdough recipes are written in baker’s percentages because the format scales without rewriting. A 75% hydration country loaf can be built from 500 grams of flour or 5,000 grams — the ratios stay identical.
Doing this conversion by hand each time is tedious, however, and most online tools quietly ignore the flour and water already inside your sourdough starter. That oversight pushes your finished dough off-target by several percentage points, which is enough to ruin a high-hydration bake.
This sourdough calculator treats the levain as part of the dough — exactly the way professional bakeries do. When you set 75% hydration, the finished bread dough is actually 75% hydration. That single detail makes the difference between a guess and a formula you can repeat every Sunday. For more general percentage and ratio math, our Percentage Calculator handles the basics outside the bread realm.
Key Features
- True Baker’s Math: Subtracts starter flour and water from the totals so your real hydration equals the number you set.
- Custom Starter Hydration: Supports 100% liquid sourdough starters, 50% stiff starters, and any feeding ratio in between.
- Instant Recipe Scaling: Bake one boule or twenty — adjust the flour input and every other ingredient updates automatically.
- Hydration Guidance: Live feedback explains what crumb structure to expect at your chosen hydration level.
- Total Dough Yield: Useful for dividing dough into batards, baguettes, dinner rolls, or pizza balls of a specific weight.
- Gram-Accurate Output: Every value displays to the nearest gram for kitchen-scale precision.
- Zero Sign-Up, Zero Cost: Open the page on any device and start baking.
Sourdough Hydration Calculator Tool
Enter your total flour weight, hydration target, salt percentage, and sourdough starter details below. Click Calculate Recipe for an instant breakdown.
Sourdough Hydration Calculator
| Ingredient | Amount |
|---|---|
| Flour to add | 0 g |
| Water to add | 0 g |
| Salt | 0 g |
| Active Starter (levain) | 0 g |
| Total Dough Weight | 0 g |
How to Use the Sourdough Hydration Calculator
- Enter total flour in grams. Sourdough bread baking is a gram-level craft — a digital kitchen scale is essential for repeatable results.
- Set your hydration percentage. A range of 70–75% is the sweet spot for beginner-to-intermediate artisan loaves.
- Enter the salt percentage. Two percent of total flour is the industry standard for most artisan breads and country loaves.
- Add your starter percentage. Twenty percent of the total flour weight is a classic levain build that ferments overnight at room temperature.
- Enter the starter's hydration ratio. Use 100% if you feed equal weights of flour and water; use 50% for a stiff starter.
- Click Calculate Recipe. You will receive precise gram amounts for every ingredient and a quick read on the expected crumb structure.
Keep a running log of each bake — what worked, what didn't — in the free Online Notepad. Patterns become obvious after five or ten bakes, and a written record beats trying to remember details after the fact.
Understanding Sourdough Hydration Ranges
The hydration percentage you choose directly shapes the crumb, crust, and handling characteristics of the finished loaf. Below is a quick reference for the most common ranges in artisan sourdough baking.
- 60–65% (low hydration): Bagels, pretzels, sandwich bread. Tight, dense crumb that slices cleanly.
- 65–72% (medium hydration): Beginner-friendly boules and batards. Forgiving dough that shapes easily.
- 72–80% (high hydration): Classic artisan country loaves. Open crumb, blistered crust, slightly sticky to handle.
- 80–90% (very high hydration): Tartine-style country bread. Slack dough that needs strong gluten development.
- 90%+ (ultra-high): Focaccia, ciabatta. Too wet to shape — pour into a pan and use stretch-and-fold development.
Benefits of Using Baker's Percentages
- Bake-to-Bake Consistency: The same formula at the same hydration produces the same loaf every time.
- Effortless Recipe Scaling: Doubling, tripling, or halving any sourdough recipe takes one input change.
- Improved Crumb Structure: Correct hydration is the single biggest factor in open crumb, oven spring, and rise.
- Recipe Translation: Convert any sourdough bread recipe online — even ones written in cups — into accurate gram-based formulas.
- Less Ingredient Waste: Mix exactly the right dough size for the pan, banneton, or batch you plan to bake.
- Quicker Troubleshooting: When a loaf disappoints, you know precisely what the hydration was, so you can adjust on the next bake.
Who Can Benefit from This Sourdough Calculator
- Home Sourdough Bakers: Anyone working through their first hundred loaves and learning how each variable changes the finished bread.
- Pastry and Flatbread Hobbyists: Bakers experimenting with focaccia, ciabatta, sourdough pizza, or rye blends.
- Micro Bakeries and Cottage Bakers: Small commercial bakers scaling daily production from one mix to many.
- Recipe Developers and Food Bloggers: Writers and YouTubers building their own sourdough formulas to publish.
- Baking Instructors and Cooking Schools: A clean teaching aid for explaining hydration and baker's percentages to new students.
- Homesteaders and Self-Sufficiency Enthusiasts: Bakers who grow their own grain or grind their own flour and want to track every variable. (Also see our Grow a Garden Calculator for planning kitchen-garden output.)
Tips for Getting the Most from the Calculator
- Weigh everything in grams. A cup of flour can vary by up to 30 g depending on how packed it is — volume is the enemy of consistency.
- Start at 70% hydration if you are new. Push higher only after you can handle that level consistently for three or four bakes.
- Reserve water for the salt addition. Hold back 10–20 g to dissolve the salt during the autolyse step.
- Adjust for flour type. Bread flour holds higher hydration well; whole wheat and rye absorb more, so add 3–5% extra water.
- Plan your bake schedule. Use the free To-Do List Maker to lay out autolyse, bulk fermentation, shaping, and cold proof times in order.
- Recalculate when you change variables. If your dough feels too slack on bake day, drop hydration 2–3% in the next session rather than adding flour during shaping.
- For broader math. Use our Basic Calculator for any general arithmetic that comes up while you are formulating new recipes.
Conclusion
The Sourdough Hydration Calculator is the kitchen companion every serious sourdough baker needs. Whether you are scaling a tested recipe, dialing in a perfect hydration target, or learning baker's percentages for the first time, this tool turns confusing formula math into a clear gram-by-gram list of ingredients. Free, instant, mobile-friendly, and built for real artisan bakers. Bookmark the page and pull it up before every bake — your loaves will be more consistent within a week of using it.
Frequently Asked Questions
Hydration is the ratio of water to flour in a dough, expressed as a percentage. A 75% hydration sourdough contains 75 grams of water for every 100 grams of flour. Higher hydration generally produces a more open, airy crumb and a stickier, harder-to-handle dough.
Yes. This is the key feature that separates this tool from most online sourdough calculators. The flour and water already in your levain are subtracted from the totals you add, so your finished dough actually matches the hydration you set.
70–72% is the sweet spot for new bakers. The dough holds its shape, is easy to handle, and still produces an open crumb when bulk fermentation and shaping are done well.
Just enter its actual hydration. If you feed it 50 g flour and 25 g water, that is a 50% (stiff) starter — the calculator will adjust every other ingredient accordingly.
Because sourdough is highly sensitive to small changes and volume measurements like cups vary too widely to be reliable. Every professional bakery in the world bakes by weight, and grams are the global standard for repeatable artisan baking.
Yes — completely free, no sign-up, no downloads, and it works on phones, tablets, and desktops anywhere you have a browser.