Sourdough Ratio Calculator

Our sourdough calculator uses baker's percentage to compute precise ingredient weights for any batch size. Start by entering your target dough weight — the total mass of the finished dough before shaping. Then adjust the hydration slider to set the water-to-flour ratio (most sourdough breads fall between 65% and 85%).

The starter percentage controls how much pre-fermented flour goes into your dough. A typical range is 15%–25% of total flour weight. Higher starter percentages speed up fermentation but can increase sourness. The salt percentage defaults to 2%, the industry standard, but you can fine-tune it to taste.

Because sourdough starter is roughly half flour and half water, the calculator automatically accounts for the flour and water contributed by the starter. This means the hydration you see is the true overall hydration of the final dough, not just the added water divided by added flour.

After calculating, you can save your recipe for later, copy the results to your clipboard, or export a printable PDF recipe card. The fermentation timing section estimates bulk fermentation duration based on your kitchen temperature — warmer rooms ferment faster while cooler temperatures slow things down and develop more complex flavors.

Deepen Your Knowledge

• Baker's Percentage Explained — the math behind this calculator
• Step-by-Step Calculator Guide — detailed walkthrough
• Fermentation Temperature Guide — timing your sourdough perfectly
• Desired Dough Temperature (DDT) — the key to consistent results