Use this free sourdough calculator to build a complete bread recipe by weight, calculate hydration percentage, or plan your next starter feeding. Enter your flour weight and adjust the sliders — every value updates instantly.
Enter how much active starter you want after feeding, then choose your feeding ratio.
How to Use This Sourdough Calculator
This sourdough calculator has three modes, each solving a different baking problem:
- Recipe Builder — Enter your total flour weight, then use the sliders to set hydration, levain percentage, and salt. Exact grams for every ingredient update instantly. Use the loaf buttons to scale for multiple loaves.
- Hydration Calculator — Enter flour and water weights to find hydration percentage. Switch to "Find Water Amount" to reverse it: set a target hydration and get the exact water in grams.
- Starter Feeding Calculator — Decide how much active starter you want after feeding, pick a ratio, and see exactly how much to keep, discard, and add.
All values use baker's percentages — every ingredient is a percentage of total flour weight. Change the flour weight and every other amount recalculates automatically. This is the method used in every professional bakery worldwide.
Understanding Sourdough Hydration
Hydration is the ratio of water to flour by weight. A recipe with 500 g flour and 375 g water is 75% hydration. This single number has more impact on texture, crust, and handling than almost any other variable.
Hydration Level Guide
| Hydration | Dough Feel | Best For | Difficulty |
|---|---|---|---|
| 60–65% | Stiff, smooth | Bagels, dense sandwich loaves | Beginner-friendly |
| 70–75% | Soft, slightly tacky | Country loaves, batards | Beginner–intermediate |
| 76–82% | Wet, sticky | Open-crumb artisan loaves | Intermediate |
| 83–90% | Very wet, shaggy | Ciabatta, baguettes | Advanced |
| 90%+ | Almost pourable | Focaccia, experimental | Expert |
Why hydration matters: Water activates gluten proteins glutenin and gliadin, forming the elastic network that traps CO2 from fermentation. Higher hydration creates a more extensible network, producing an open, irregular crumb. The trade-off: wetter doughs require more practice with coil folds, slap-and-fold, and lamination.
Flour type matters. Whole wheat and rye absorb more water than white flour due to bran content. Replace 20% of white flour with whole wheat and add 2–5% more hydration to maintain the same dough feel.
Sourdough Starter Percentage
The levain percentage controls fermentation speed and bread flavor. Higher percentage = faster fermentation and milder tang. Lower percentage = slower fermentation with more complex, acidic notes.
| Starter % | Bulk Ferment Time at 24°C | Flavor Profile |
|---|---|---|
| 5–10% | 12–18 hours | Very sour, complex, deep acidity |
| 15–20% | 6–10 hours | Balanced tang — most popular range |
| 25–35% | 3–5 hours | Mild, lightly tangy |
Temperature amplifies everything. At 26°C a 20% inoculation might finish in 5 hours. At 20°C the same recipe takes 10–12 hours. Track your kitchen temperature and adjust starter percentage or timing accordingly.
How to Feed Your Sourdough Starter
A feeding ratio like 1:2:2 reads as starter kept : flour added : water added. Higher ratios extend the time to peak activity.
| Ratio | Time to Peak | Best For |
|---|---|---|
| 1:1:1 | 6–8 hours | Daily bakers, warm kitchens |
| 1:2:2 | 8–12 hours | Most home bakers |
| 1:3:3 | 12–16 hours | Baking every other day |
| 1:5:5 | 16–24 hours | Weekly bakers |
Baker's Percentage Explained
Every ingredient is expressed as a percentage of total flour weight. Flour is always 100%. Example with 500 g flour: water 375 g (75%), starter 100 g (20%), salt 10 g (2%) = 985 g total dough. To scale to 750 g flour, multiply every weight by 1.5. The percentages stay the same, results stay identical. The Recipe Builder above does this automatically.
Essential Tools for Sourdough Baking
- Digital kitchen scale (1g precision) — The most important tool. A quality kitchen scale eliminates measurement error and makes every batch reproducible.
- Banneton / proofing basket — Supports the shaped loaf during cold retard. Creates the classic spiral pattern on the crust.
- Dutch oven or combo cooker — Traps steam during the first 20 minutes of baking, enabling maximum oven spring and a crackling crust.
- Metal bench scraper — Divides dough and builds surface tension during pre-shaping without extra flour.
- Lame or bread scoring tool — Controls where the loaf opens. A sharp blade at 30–45° produces the classic ear.
- Instant-read thermometer — Confirms the loaf is done. Target 96–99°C (205–210°F) at the center.
Find the Right Scale for Sourdough Baking
A digital kitchen scale with 1g precision is more important than any special flour or technique upgrade. It is the one tool that makes every other variable controllable.
Shop Kitchen Scales →
