Free Sourdough Hydration Calculator

Quick answer: Hydration is the soul of sourdough — it decides whether your crumb is open and airy or tight and dense. But most calculators get the math wrong by ignoring the flour and water already hiding in your starter. This free sourdough hydration calculator is starter-aware: tell it your flour, starter weight, and starter hydration, and it computes exactly how much water to add for your target hydration — plus a full baker's-percentage table and total dough weight. Everything runs in your browser; no signup, no ads.

Hydration is the soul of sourdough — it decides whether your crumb is open and airy or tight and dense. But most calculators get the math wrong by ignoring the flour and water already hiding in your starter. This free sourdough hydration calculator is starter-aware: tell it your flour, starter weight, and starter hydration, and it computes exactly how much water to add for your target hydration — plus a full baker's-percentage table and total dough weight. Everything runs in your browser; no signup, no ads.

How to Use the Sourdough Hydration Calculator

1. Pick a mode: 'Target hydration → water' tells you how much water to add; 'Water → actual hydration' tells you the hydration of the water you're about to use.
2. Enter your flour weight, starter weight, and your starter's hydration (100% means equal parts flour and water).
3. Enter your target hydration — or your planned water amount — and your salt percentage (2% is standard).
4. Click Calculate: you get the exact water to add, the true total hydration, a baker's-percentage table, and total dough weight.
5. Adjust and recalculate freely — the math updates instantly, so dial in your formula before you mix.

Why Use Our Sourdough Hydration Calculator?

• Starter-aware math — the flour and water inside your starter are counted, so the hydration number is the true total, not a rough guess.
• Two directions — solve for the water you need, or check the hydration of the water you planned.
• Baker's percentages — every ingredient expressed as a percentage of total flour, the professional baker's standard.
• Salt + dough weight — salt at your chosen percentage and the final dough weight, ready for dividing into loaves.
• 100% private — runs entirely in your browser; your recipes never leave your device.

Common Use Cases

• Dial in a new recipe: Start at 72–75% hydration, bake, then nudge up or down — the calculator keeps the math exact as you iterate.
• Scale a recipe up or down: Keep baker's percentages fixed and the tool rescales flour, water, starter, and salt proportionally.
• Convert a recipe to baker's %: Paste a friend's cup-and-spoon formula into grams, and the calculator reveals the true hydration hiding inside.
• Troubleshoot a gummy crumb: Check whether your actual hydration (including the starter's water) was higher than you thought — the usual culprit.
• Teach a baking class: Show students live how changing starter hydration from 100% to 80% shifts the water needed — arithmetic they can see.

Sourdough Hydration Calculator vs Alternatives

• Recipe blogs with fixed formulas: Great for a first bake, but a fixed '350 g water' can't adapt to your flour. Ours recalculates for any flour, starter, or hydration.
• Bread-baking apps: Handy for timers and journals, but most bake the starter math in wrong or hide it. Ours shows every number and counts the starter properly.
• Spreadsheet calculators: Accurate if you build the starter correction yourself — most don't. This does the correction automatically in one click.
• Asking in r/Breadit: The community is wonderful for technique, but for arithmetic a calculator is faster — and never argues about 73% vs 75%.

If you bake the same formula every week, memorize it and skip the calculator. For everything else — new flours, recipe conversions, class demos, scaling — starter-aware math in one click beats mental arithmetic and beats the calculators that pretend your starter is pure flour.

Frequently Asked Questions