Sourdough Starter Calculatorv1.0.0

Choose a calculation mode, enter your starter details, and read the exact flour and water amounts in the results panel. The calculator accepts whole numbers, decimals, fractions like 3/4, and mixed numbers like 1 1/2, so you can match whatever measurement style your recipe uses.

• Maintain Existing Starter: Apply a feeding ratio (such as 1:1:1 or 1:2:2 starter to flour to water) to your current starter weight and read the flour and water to add at the next feeding.
• Scale to Target Amount: Calculate the flour and water needed to reach a target final weight while preserving the chosen starter, flour, and water ratio.
• Adjust Hydration Level: Convert a starter from one hydration percentage to another by reporting how much water to add or remove.

• Maintenance feed: flour to add = current starter weight times (flour ratio divided by starter ratio); water to add uses the same pattern with the water ratio.
• Scaling: flour or water needed = target weight times (flour or water ratio divided by total ratio), where total ratio = starter + flour + water.
• Hydration: flour weight = starter weight divided by (1 + hydration percent divided by 100); target water weight = flour weight times (target hydration percent divided by 100).

Switch the unit system between grams, ounces, and cups in the Settings panel. Enable Show step-by-step calculations to see each formula and substitution behind the result, which is useful for verifying recipes or teaching baker percentages.

Reach for the calculator any time a recipe, feeding schedule, or hydration target requires precise flour and water amounts derived from your current starter weight.

• Daily home feeding: Maintain a small 30 to 60 gram starter on a 1:1:1 ratio without doing the arithmetic by hand each morning.
• Recipe scaling: Build a levain for a specific bread recipe by entering the target weight and chosen ratio, then read the flour and water to add.
• Hydration conversion: Switch a 100 percent hydration starter to a stiffer 60 to 80 percent starter for recipes that call for a firm levain, or move in the other direction for liquid starters.
• Bakery production: Scale a small maintenance starter up to multi-kilogram production weights while keeping the original ratio intact, with results readable in grams or ounces.
• Travel and storage: Calculate the flour and water needed to revive a dehydrated or refrigerated starter back to a working hydration before a bake.
• Multi-flour starters: Track separate whole wheat, rye, and white flour starters that each run on different feeding ratios and hydration levels.
• Teaching baker math: Demonstrate how starter, flour, and water ratios convert into real gram weights, with the step-by-step view showing each formula and substitution.
• Troubleshooting: Experiment with stiffer or wetter feedings when a starter is sluggish or overly acidic, and see the resulting weights before mixing.
• Class instruction: Project the calculator during a sourdough workshop to walk students through ratio changes in real time, swapping flour weights and watching every dependent value update at once.

Healthy starters double in volume within four to twelve hours after feeding at room temperature, depending on flour type, hydration, and ambient temperature. Use the calculator as a planning aid alongside visual cues like rise, smell, and bubble structure rather than replacing them. When refrigerating between bakes, plan two or three room-temperature feedings before a bake day to bring the starter back to peak activity, and rerun the calculator each time the target weight or ratio changes.