Sourdough Hydration Calculator
Precise Baker’s Math for home bakers. No mental math. No spreadsheets. Just perfect dough ratios every time.
Sourdough Hydration Calculator
Enter your ingredient weights below. This sourdough hydration calculator accounts for the flour and water already in your starter — so your hydration figure is always 100% accurate.
📊 Your Dough Results
What Is Sourdough Hydration and Why Does It Matter?
Hydration refers to the ratio of water to flour in your dough, expressed as a percentage using Baker’s Math. Using a sourdough hydration calculator is the most accurate way to get this right — it is the single most important variable controlling your bread’s texture, crumb structure, and crust. Get it right and your loaf springs open beautifully. Get it wrong and you end up with a dense, gummy interior — one of the most common signs covered in our guide to identifying underproofed sourdough bread.
A lower hydration dough (60–68%) is stiffer, easy to handle, and produces a tight, even crumb — perfect for sandwich loaves. A higher hydration dough (75–85%) is slack and sticky but rewards you with the open, airy crumb and crispy crust that artisan sourdough is famous for. Learning to work with higher hydration takes practice, but our sourdough for beginners guide walks you through every step.
Baker’s Math rule: Flour is always 100%. Every other ingredient — water, starter, salt — is expressed as a percentage of the total flour weight. This makes scaling any recipe up or down effortless.
Want to go deeper on Baker’s Math? The King Arthur Baking reference on Baker’s Percentages is one of the most thorough explanations available — a great bookmark alongside this calculator.
What Is Considered High Hydration Sourdough?
Any dough above 75% hydration is generally considered high hydration. Use this sourdough hydration calculator to dial in any level before you mix your dough. Above 80%, you are working with a very slack dough that requires strong technique — confident shaping, proper bench rest, and good gluten development through stretch-and-folds. If you are new to sourdough, start at 70% and work your way up as your confidence grows.
How to Use This Calculator
Unlike a basic water-to-flour ratio tool, this sourdough hydration calculator accounts for the flour and water already inside your sourdough starter — giving you a true, accurate dough hydration figure. Here’s how to use it:
Enter your flour weight — this is the main flour in your recipe, not including any flour inside your starter.
Enter your water weight — again, just the water you are adding to the dough, not the water inside your starter.
Enter your starter weight — the full weight of starter your recipe calls for (e.g. 100g).
Set your starter’s hydration — most home bakers use a 100% hydration starter (equal parts flour and water by weight). If you feed 1:1 flour to water, leave the slider at 100%. Learn more in our sourdough starter beginner’s guide.
Enter your salt (optional) — this won’t affect hydration but will show you your salt percentage so you can confirm it is near the recommended 2%.
Click Calculate — your true dough hydration, total flour, total water, and all Baker’s Percentages appear instantly.
Pro tip: If your starter is at 100% hydration and you use 100g of starter, that means 50g of flour and 50g of water are already in your dough — before you add anything else. Always account for this, or your hydration calculation will be off.
How to Calculate Sourdough Hydration by Hand
If you want to understand the math behind the calculator, here is the formula:
Find the flour from your starter: Starter weight ÷ (1 + starter hydration as decimal). For a 100g starter at 100% hydration: 100 ÷ 2 = 50g flour from starter.
Find the water from your starter: Starter weight − starter flour. So 100 − 50 = 50g water from starter.
Add up total flour: Recipe flour + starter flour. E.g. 500 + 50 = 550g total flour.
Add up total water: Recipe water + starter water. E.g. 350 + 50 = 400g total water.
Calculate hydration: (Total water ÷ Total flour) × 100. So (400 ÷ 550) × 100 = 72.7% hydration.
That is a lot of mental math mid-bake. That is exactly why this sourdough hydration calculator exists — so you can focus on the dough, not the arithmetic.
Sourdough Hydration Chart — Quick Reference Guide
Bookmark this chart alongside the sourdough hydration calculator above and use both every time you plan a bake. They tell you what to expect from your dough at each hydration level and which recipes each suits best.
| Hydration | Dough Feel | Best For | Skill Level |
|---|---|---|---|
| 60–65% | Stiff, easy to handle | Bagels, pretzels, crackers | ⭐ Beginner |
| 66–72% | Firm, smooth, manageable | Sandwich loaves, dinner rolls | ⭐ Beginner |
| 73–78% | Soft, slightly tacky | Artisan boules, batards | ⭐⭐ Intermediate |
| 79–85% | Slack, sticky, wet | Open-crumb artisan loaves | ⭐⭐⭐ Intermediate |
| 86–90% | Very wet, flows | Ciabatta, focaccia | ⭐⭐⭐⭐ Advanced |
| 90%+ | Extremely slack | Flatbreads, specialty loaves | ⭐⭐⭐⭐⭐ Expert |
Run any of these values through the sourdough hydration calculator above before you mix. For your first few loaves, aim for 70–72% hydration. Once you are comfortable with shaping and stretch-and-fold techniques from our beginner’s sourdough guide, push up to 75–78% for that classic open crumb.
Real Recipe Examples at Different Hydration Levels
Seeing hydration in action with real recipes makes it far easier to understand. Here are three examples from our recipe collection — each at a different hydration level. Plug these numbers into the sourdough hydration calculator above to see exactly how they work.
Example 1 — 72% Hydration: Classic Sourdough Sandwich Bread
500g bread flour · 325g water · 100g starter (100% hydration) · 10g salt. The calculator gives you: total flour 550g, total water 375g, true hydration: 68%. This is an approachable, workable dough that holds its shape well — perfect for our whole wheat sourdough sandwich bread.
Example 2 — 78% Hydration: Artisan Boule
500g bread flour · 375g water · 100g starter (100% hydration) · 10g salt. True hydration: 77%. A soft, slightly tacky dough that produces beautiful oven spring and an open crumb when handled correctly. This is the sweet spot for home bakers ready to move beyond beginner loaves.
Example 3 — 85%+ Hydration: Sourdough Discard Flatbread
When you have leftover discard you want to use immediately, sourdough flatbread is the perfect high-hydration, no-fuss option. The very wet batter comes together in minutes and cooks directly on a hot pan — no shaping skills needed.
5 Common Hydration Mistakes (And How to Fix Them)
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Not accounting for starter hydrationThe most common error. If you add 100g of starter and ignore the 50g of water it contains, your dough is wetter than your recipe intends. Always use this sourdough hydration calculator to get the true number — it splits your starter into its flour and water components automatically.
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Using warm water in a warm kitchenWater temperature affects fermentation speed. In a warm kitchen (above 24°C/75°F), use cooler water to slow things down. Overfermented dough goes slack and becomes impossible to shape — and looks a lot like underproofed sourdough when baked.
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Switching flour types without adjusting waterWhole wheat and rye flour absorb significantly more water than white bread flour. If you swap flours without reducing water, your dough will be much wetter than expected. Reduce water by 5–10% when switching to whole grain flours.
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Measuring by volume instead of weightA cup of flour can weigh anywhere from 120g to 160g depending on how it is scooped. Hydration percentages only make sense when you use a kitchen scale. According to Serious Eats’ baking measurement guide, volume measurements for flour can vary by up to 30% depending on scooping technique — reason enough to invest in a good scale.
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Adding all the water at onceHold back 10–15% of your water when you first mix your dough (called “bassinage”). Once the gluten has developed slightly, add the reserved water gradually. This is especially important above 75% hydration, and something covered in depth in our sourdough for beginners guide.
How to Determine Your Sourdough Starter’s Hydration
Your starter has its own hydration, and it feeds directly into your dough’s total water content. The Perfect Loaf’s sourdough starter guide is an excellent companion resource for understanding how starter health affects dough hydration. If you feed your starter with equal weights of flour and water — say, 50g flour + 50g water — your starter is at 100% hydration. This is the most common approach for home bakers and what most recipes assume.
If you feed 2 parts flour to 1 part water (e.g. 100g flour + 50g water), your starter is at 50% hydration — a stiff starter. Some European bakers prefer stiff starters for a milder, less tangy flavor. Once you know your starter’s hydration, enter it into the sourdough hydration calculator slider above for a precise result. If you haven’t built your starter yet, our step-by-step sourdough starter recipe shows you exactly how to create and maintain one from scratch.
Quick formula: Starter hydration % = (water in starter ÷ flour in starter) × 100. A 100g starter fed with 50g flour and 50g water = (50 ÷ 50) × 100 = 100% hydration.
Ready to Bake? Try These Recipes Next
Now that you have your hydration dialed in, pick a recipe and start baking. Each one includes precise gram measurements so you can plug them straight into the calculator above.
Frequently Asked Questions
Baker’s Math (or Baker’s Percentages) expresses every ingredient as a percentage of the total flour weight, which is always set at 100%. This system makes it easy to scale recipes up or down, compare different formulas, and understand how ingredient ratios affect the final bread. For example, a typical sourdough formula is: 100% flour, 70–75% water, 20% starter, and 2% salt.
Most home bakers use between 15–25% starter relative to flour weight. In warmer kitchens (above 24°C/75°F), use less starter (10–15%) to slow fermentation. In cooler kitchens (below 19°C/66°F), use more starter (25–30%) to keep fermentation moving. The calculator sets a default of 20% — a reliable middle ground year-round.
Use this sourdough hydration calculator and aim for 70–72% true dough hydration as a beginner. This gives you a workable, shapeable dough without being too sticky to handle. Once you have made 3–5 loaves and feel comfortable with stretch-and-folds and shaping, increase to 75%. See our sourdough for beginners guide for full technique instructions.
Several factors can make dough feel wetter than expected: the type of flour (whole wheat absorbs more water), ambient temperature (warm kitchens make dough slacker), over-fermentation, and not accounting for the water in your starter. Use this sourdough hydration calculator to verify your true hydration, and always weigh ingredients rather than measuring by volume.
No — salt does not count toward hydration. Hydration is purely the ratio of water to flour. However, salt does affect fermentation (it slows it slightly) and gluten strength (it tightens the dough). The standard amount is 2% of flour weight. For a 500g flour recipe, that is 10g of salt — a good benchmark for balanced flavor without overpowering the sourdough tang.
Use the starter hydration slider and set it to 80%. The calculator will correctly split your starter weight into its flour and water components using that ratio, giving you an accurate total dough hydration. This is especially important for bakers who maintain stiff starters or liquid levains at non-standard hydrations.
New to Sourdough?
Start from the very beginning — learn how to build your starter from scratch, mix your first dough, and bake a loaf you’ll be proud of.
Start the Beginner’s Guide →