Sourdough Calculator

Your expert tool for perfect baker’s percentages and consistent loaves.

What is a Sourdough Calculator?

A sourdough calculator is a specialized tool designed for bakers to formulate bread recipes using baker’s percentages. Instead of working with fixed measurements like cups or spoons, a sourdough calculator determines the precise weight of each ingredient (flour, water, salt, and starter) based on ratios relative to the total flour. This method ensures scalability and consistency, allowing you to easily adjust your loaf size or hydration level while maintaining the same fundamental dough characteristics.

This approach is critical for sourdough because the hydration level—the amount of water relative to the flour—dramatically affects the dough’s handling, fermentation speed, and final crumb structure. By using a sourdough calculator, bakers can move beyond simple recipes and gain full control over their dough formulation for repeatable, professional results.

Sourdough Calculator Formula and Explanation

The core of a sourdough calculator revolves around baker’s math, where total flour is always the 100% base unit. All other ingredients are a percentage of that flour weight. The main goal is to solve for the Total Flour needed to achieve a desired loaf weight with specific percentages.

The primary formula is:

Total Flour (g) = Target Loaf Weight / (1 + Hydration % + Salt %)*

*Note: The starter is not added to this denominator because it is composed of flour and water, which are already accounted for in the total flour and water calculations. The total weight is the sum of Total Flour, Total Water, and Salt.

Once Total Flour is found, all other ingredients are calculated from it:

• Total Water (g) = Total Flour × (Hydration % / 100)
• Salt (g) = Total Flour × (Salt % / 100)
• Total Starter (g) = Total Flour × (Starter % / 100)

Finally, to get the actual recipe you’ll mix, we must subtract the flour and water already present in the starter:

• Flour in Starter (g) = Total Starter / (1 + Starter Hydration %)
• Water in Starter (g) = Total Starter – Flour in Starter
• Flour to Add (g) = Total Flour – Flour in Starter
• Water to Add (g) = Total Water – Water in Starter

Variables Table

Variable	Meaning	Unit	Typical Range
Loaf Weight	The final target weight of your dough.	grams (g)	500 – 2000 g
Hydration	Total water relative to total flour.	%	65 – 85%
Starter %	The amount of leaven relative to total flour.	%	10 – 30%
Salt %	Salt relative to total flour. Controls flavor and fermentation.	%	1.8 – 2.2%

Practical Examples

Example 1: Classic 75% Hydration Loaf

Let’s say you want a standard 900g loaf with a moderately open crumb.

• Inputs: Loaf Weight = 900g, Hydration = 75%, Starter = 20%, Salt = 2%, Starter Hydration = 100%.
• Results:
  • Flour to Add: 413g
  • Water to Add: 330g
  • Starter to Add: 101g
  • Salt to Add: 10g
• This creates a dough that is manageable for most bakers and yields a classic sourdough loaf.

Example 2: High-Hydration 82% Loaf

For a more open, airy crumb (and a more challenging dough to handle), you might increase the hydration.

• Inputs: Loaf Weight = 900g, Hydration = 82%, Starter = 15%, Salt = 2%, Starter Hydration = 100%.
• Results:
  • Flour to Add: 421g
  • Water to Add: 371g
  • Starter to Add: 76g
  • Salt to Add: 10g
• Notice how the “Water to Add” increased significantly, which will result in a stickier, more extensible dough.

How to Use This Sourdough Calculator

1. Set Your Goal: Start by entering your desired Target Loaf Weight in grams. A typical home-baked loaf is between 750g and 1000g.
2. Define Hydration: Input your target Dough Hydration. If you are a beginner, starting between 70-75% is recommended. Higher hydration (80%+) leads to a more open crumb but is harder to work with.
3. Choose Leaven Amount: Set the Starter Percentage. A higher percentage (like 25-30%) will lead to a faster bulk fermentation, while a lower percentage (10-15%) will slow it down, often developing more flavor.
4. Add Salt: A Salt Percentage of 2% is standard. Adjusting between 1.8% and 2.2% is safe. Salt strengthens gluten and controls fermentation speed.
5. Review the Recipe: The calculator instantly provides the primary result: the exact weights of flour, water, starter, and salt you need to mix together.
6. Analyze the Data: Use the intermediate values and the composition table to understand the total flour and water in your formula, which is helpful for advanced recipe development.

Key Factors That Affect Sourdough Baking

• Flour Type: Whole wheat and rye flours absorb more water than white bread flour. If you use a high percentage of whole grains, you may need to increase the hydration to achieve a similar dough consistency. A guide to flour types can be very helpful.
• Starter Health: The activity of your starter is paramount. A vigorous, recently fed starter will ferment the dough much faster than a sluggish one. Our sourdough starter guide covers this in detail.
• Ambient Temperature: Temperature is a major catalyst. A warm kitchen (78°F / 26°C) will significantly speed up bulk fermentation and proofing times compared to a cool one (68°F / 20°C). This is a key principle in baking science.
• Hydration Level: This is more than just a number; it changes everything. Higher hydration doughs ferment faster and produce a more open, tender crumb but require more skill in handling and shaping. Lower hydration doughs are stiffer, easier to handle, and produce a tighter crumb.
• Salt Percentage: Salt is not just for flavor. It tightens the gluten network and slows down fermentation by inhibiting yeast and bacterial activity. Reducing salt too much can lead to a sticky, weak dough that ferments too quickly.
• Bulk Fermentation Time: This is the dough’s first rise. Properly judging the end of bulk fermentation—usually by a 30-50% volume increase and signs of aeration—is more important than strictly following a clock. Our fermentation guide is a must-read.

Frequently Asked Questions (FAQ)

1. What hydration level is best for a beginner?
Starting with a hydration level between 68% and 72% is ideal for beginners. This range produces a dough that is manageable and less sticky, making it easier to practice shaping techniques while still yielding a great loaf.

2. Why are weights in grams used instead of cups?
Baking is a science, and grams are a precise unit of mass, whereas cups are a unit of volume. The density of flour can vary significantly, so a cup of flour can have a different weight each time, leading to inconsistent results. A sourdough calculator relies on the accuracy of weight measurements.

3. How does starter percentage affect my bread?
A higher starter percentage (e.g., 25%) will make your dough ferment faster. A lower percentage (e.g., 10-15%) will result in a longer, slower fermentation, which can develop a more complex, sour flavor.

4. My starter is not at 100% hydration. How do I use it?
This calculator is designed for that! Simply enter your starter’s hydration in the “Starter Hydration” field. The calculator will automatically adjust the flour and water amounts needed for your main dough mix.

5. What is “baker’s percentage”?
It’s a universal method in baking where the total weight of flour in a recipe is set to 100%. Every other ingredient is then expressed as a percentage of that flour weight. It simplifies scaling recipes up or down.

6. Why is my calculated loaf weight slightly different from the target?
This is due to rounding in the calculations to provide workable numbers (usually to one decimal place). There is also a small amount of weight loss (moisture evaporation) that occurs during baking, typically 10-15%.

7. Can I use this calculator for other types of bread?
While this is a dedicated sourdough calculator, the principles of baker’s percentages can be applied to other breads. However, the inputs and typical ranges are optimized for sourdough. You may find our general bread calculator more suitable for yeasted doughs.

8. How do I get a more open crumb?
A more open crumb is typically achieved with higher hydration (78%+), strong flour, proper dough development (e.g., stretch and folds), and correct proofing. However, it requires more advanced dough handling skills.

Related Tools and Internal Resources

Expand your baking knowledge with our other specialized tools and guides:

• Pizza Dough Calculator – Create the perfect pizza base with adjustable hydration and fermentation times.
• Bread Flour Blend Calculator – Formulate custom flour mixes for unique flavors and textures.
• Starter Feeding and Maintenance Guide – A comprehensive look at keeping your sourdough starter active and healthy.