Sourdough Calculator

What This Sourdough Calculator Does

This calculator takes the guesswork out of scaling sourdough recipes. Instead of manually recalculating baker's percentages every time you adjust batch size or hydration, you enter your target dough weight and desired hydration level, and the tool outputs precise gram amounts for starter, flour, water, and salt.

The core assumption is a standard 100% hydration starter (equal parts flour and water by weight). This is the most common maintenance ratio for home bakers and provides a reliable baseline for consistent results.

How the Calculations Work

The calculator uses baker's percentages, where flour weight is always 100%. All other ingredients are expressed as a percentage of that flour weight.

The standard formula for a basic sourdough loaf looks like this:

• Flour: 100% (base ingredient)
• Water: Variable (typically 65% to 85% for sourdough)
• Starter: Variable (typically 20% to 30% of flour weight)
• Salt: 2% (standard for most bread recipes)

When you enter a target dough weight and hydration percentage, the calculator works backward from these ratios. It first determines the total flour weight needed, then calculates the water weight based on your hydration input, and finally computes the starter and salt amounts proportionally.

Because the starter itself contains flour and water, the calculator accounts for those contributions. The final flour and water amounts shown are the additional ingredients you need to add, not the total including the starter.

How to Use the Calculator

1. Set your target dough weight. Decide how much finished dough you want. A standard loaf is typically 800g to 1000g.
2. Choose your hydration percentage. Lower hydration (65-70%) produces a firmer dough that's easier to shape. Higher hydration (75-85%) creates an open crumb and softer texture but is stickier to handle.
3. Adjust the starter percentage (optional). The default is 20%. Increase it for faster fermentation or a more pronounced sour flavor. Decrease it for longer, slower fermentation.
4. Read the results. The output shows the exact grams of flour, water, starter, and salt you need to mix.

Understanding Your Results

The output is divided into four ingredient amounts. Here's what each number represents:

• Flour: The weight of flour you add directly to the mixing bowl. This excludes the flour already present in your starter.
• Water: The weight of water you add directly. This excludes the water already in your starter.
• Starter: The total weight of active, bubbly starter to add. This is the full amount, not just the flour or water portion.
• Salt: The weight of salt. Fine sea salt or table salt is assumed. Coarse salts may need slight adjustment by weight.

The total of these four numbers should equal your target dough weight. If it doesn't, check that your inputs are within reasonable ranges.

Common Mistakes to Avoid

• Using a non-100% hydration starter. If your starter is stiffer or more liquid than equal parts flour and water, the calculator's assumptions will be off. Adjust your starter to 100% hydration before using this tool, or manually account for the difference.
• Misreading the flour amount. The flour shown is what you add separately. Do not double-count the flour already in your starter.
• Ignoring water temperature. The calculator gives weight, not temperature. You still need to manage dough temperature separately for consistent fermentation timing.
• Using volume measurements. This calculator works in grams. Converting cups to grams introduces significant inaccuracy. Weigh your ingredients for reliable results.

Practical Use Cases

• Scaling a recipe up or down. Easily adjust a single loaf recipe to make two loaves, or scale down a large batch for a test bake.
• Experimenting with hydration. Systematically test different hydration levels (70%, 75%, 80%) while keeping total dough weight constant to see how it affects crumb and texture.
• Adapting a recipe to a different starter percentage. If a recipe calls for 30% starter but you prefer a milder flavor with 15%, the calculator rebalances the other ingredients automatically.
• Teaching or sharing recipes. Provide exact gram amounts for others, removing ambiguity from percentage-based instructions.

Limitations

• The calculator assumes a 100% hydration starter. If your starter ratio differs, the results will not be accurate.
• It does not account for inclusions like seeds, nuts, dried fruit, or whole grain additions. Those must be added separately.
• It assumes a standard 2% salt ratio. Some recipes use less (1.5%) or more (2.5%). Adjust manually if needed.
• It provides ingredient weights only. Fermentation time, temperature, and technique are not factored in.