Sourdough Starter Calculator
Calculate the exact proportions of flour, water, sourdough starter, and salt for your perfect loaf. Uses baker's percentage and supports all hydration levels.
Your Recipe
1000g ≈ 1 large loaf • 500g ≈ 1 small loaf
Typical: 15-25%
Standard: 2%
Your Ingredients
Flour
Bread flour recommended
Water
Room temperature (~25°C)
Sourdough Starter
100% hydration, active & bubbly
Salt
Fine sea salt preferred
Hydration: 70% • Starter: 20% • Salt: 2%. All percentages are relative to flour weight (baker's math).
Basic Sourdough Bread Steps
Mix & Autolyse
Combine flour and water. Rest 30-60 min to hydrate gluten before adding starter and salt.
Add Starter & Salt
Incorporate active starter and salt using the Rubaud method or pinch-and-fold technique.
Bulk Fermentation
Perform 3-4 sets of stretch-and-folds over 4-6 hours at room temperature (24-26°C).
Pre-shape & Bench Rest
Gently shape into a round, let rest 20-30 min to relax the gluten.
Final Shape & Cold Proof
Shape tightly into a boule or batard. Place in a banneton and refrigerate 8-16 hours.
Bake
Preheat dutch oven to 250°C. Score the dough, bake covered 20 min, uncovered 20-25 min until golden.
Frequently Asked Questions
Free Sourdough Bread Calculator — Perfect Ratios Every Time
Making sourdough bread at home is one of the most rewarding culinary experiences, but getting the ingredient ratios right can be challenging, especially for beginners. Our free sourdough calculator takes the guesswork out of the process by using established baker's percentage formulas to compute the exact weight of flour, water, sourdough starter, and salt you need for any size loaf.
Whether you're baking a single 500g boule for dinner or scaling up to a 5kg batch for a weekend bake-off, this tool handles the math instantly. Simply enter your desired dough weight, pick a hydration level (60% for stiff doughs, 70% for standard country loaves, or 80%+ for high-hydration ciabattas and focaccias), and adjust the starter and salt percentages to match your preferences and your starter's activity level.
Why Use Baker's Percentage?
Baker's percentage is the international standard used by professional bakers worldwide. Unlike volumetric measurements (cups, tablespoons), it uses weight-based ratios where flour is always the 100% reference point. This makes recipes infinitely scalable and reproducible. Our calculator automatically applies these formulas, accounting for the flour and water already present in your sourdough starter (assumed to be at 100% hydration).
Everything Runs Locally
All calculations happen entirely in your browser — no data is sent anywhere, no accounts needed, and it works offline. Bookmark this page and use it whenever you're ready to bake your next loaf.