Introduction
Sourdough baking is a science as much as an art, and precise baker’s math is the difference between a beautiful open-crumb loaf and a dense disappointment. A Sourdough Calculator handles the critical calculations automatically: breaking down your starter into its flour and water components, determining the true total hydration of your dough, and calculating the final dough weight. This matters because your starter’s own hydration affects the overall water content of your recipe a factor that beginners often overlook when adjusting hydration levels. The tool also estimates ingredient costs so you can see exactly what each handmade loaf costs. Whether you are dialing in your first sourdough or experimenting with high-hydration recipes, Toolraxy provides a free, client-side calculator that brings professional baker’s math to your home kitchen.
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How to Use the Sourdough Calculator
Select your preferred currency from the dropdown.
Enter your starter percentage as a percentage of total flour weight.
Enter the flour weight and select the unit: grams, kilograms, ounces, or pounds.
Enter the water amount and select the unit: milliliters, liters, fluid ounces, or cups.
Enter the salt weight and select the unit.
Enter your starter weight and select the unit.
Enter your starter hydration percentage typically 100% for a standard 1:1 starter.
Enter ingredient costs per unit for flour, water, salt, and starter.
Click Calculate. The tool displays starter flour and water breakdown, total flour, total water, total dough weight, total hydration percentage, and ingredient cost.
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How the Tool Works
This Sourdough Calculator applies professional baker’s math formulas to account for the flour and water contained within the starter, which are often overlooked in casual recipe calculations.
Starter Breakdown Formulas:
A sourdough starter is a mixture of flour and water. The hydration percentage of the starter determines the ratio:
Starter Flour = Starter Weight รท (1 + Starter Hydration รท 100)
Starter Water = Starter Weight – Starter Flour
For a 100% hydration starter (equal parts flour and water by weight), a 100g starter contains 50g flour and 50g water. For a 50% hydration stiff starter, a 100g starter contains 66.7g flour and 33.3g water.
Total Dough Formulas:
Total Flour = Flour Added + Starter Flour
Total Water = Water Added + Starter Water
Total Dough Weight = Total Flour + Total Water + Salt
Total Hydration = (Total Water รท Total Flour) ร 100%
The total hydration is higher than simply dividing added water by added flour because the starter contributes both water and flour. This is the most common source of error in casual sourdough calculations.
Unit Conversions:
Flour, salt, and starter accept grams, kilograms, ounces, or pounds, all converted to grams for calculation. Water accepts milliliters, liters, fluid ounces, or cups, all converted to milliliters. Results display in grams and milliliters for precision.
Hydration Classification:
The calculator classifies total hydration into four ranges:
80%+ : High hydrationโsticky but airy, great for open crumb
65โ79% : Classic artisan sourdough range, perfect for most loaves
55โ64% : Firm dough, good for beginners or denser breads
Below 55% : Low hydrationโideal for bagels or very firm dough
Cost Calculation:
Flour cost is calculated per kilogram, water per liter, salt per kilogram, and starter per kilogram. Total cost is the sum of all four ingredient costs. Cost per 100g of flour and cost per loaf are also displayed.
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Worked Example
Consider a standard sourdough recipe with 500g flour, 375g water, 10g salt, and 100g of 100% hydration starter:
Starter breakdown: Starter flour = 100 รท (1 + 1.0) = 50g. Starter water = 100 – 50 = 50g.
Total flour: 500 + 50 = 550g.
Total water: 375 + 50 = 425g.
Total dough weight: 550 + 425 + 10 = 985g.
Total hydration: (425 รท 550) ร 100 = 77.3%.
Hydration classification: “Classic artisan sourdough range.”
Cost at $2.50/kg flour, $0.50/L water, $1.00/kg salt, $0.50/kg starter: flour $1.38, water $0.21, salt $0.01, starter $0.05. Total: $1.65 per loaf.
This example reveals a key insight: the true hydration is 77.3%, not the 75% you would calculate by simply dividing 375g water by 500g flour. The starter’s 50g of water raises the hydration significantly. Understanding this helps bakers adjust recipes correctlyโif you wanted a true 75% hydration, you would reduce the added water.
FAQs
How accurate is this sourdough calculator?
The baker’s math formulas are exact. The starter breakdown calculation precisely accounts for the flour and water in your starter. The hydration calculation is the true hydration, unlike simplified recipes that ignore starter water. Input accuracy determines output accuracy.
What hydration should my sourdough starter be?
The most common starter hydration is 100%, meaning equal weights of flour and water. This is easy to maintain and measure. Stiff starters (50โ60%) require more effort to mix but produce more sour flavor. Liquid starters (above 100%) are easier to mix but ferment faster. Enter your specific starter hydration for accurate calculations.
Why does the calculator ask for starter percentage separately from starter weight?
Starter percentage is the baker’s math referenceโhow much starter relative to total flour. The starter weight is the actual amount you are using. The percentage is provided for recipe context and planning, while the weight is used in the actual calculations. In practice, the starter weight determines everything; the percentage field helps you see the ratio at a glance.
How do I convert my recipe from baker’s percentages to weights?
Multiply the flour weight by each ingredient’s percentage to get the weight. For example, 20% starter on 500g flour means 100g of starter. 75% water means 375g of water. 2% salt means 10g of salt. The calculator works the other directionโenter weights and see the resulting hydrationโbut the math is reversible.
What does total hydration tell me about my bread?
Total hydration predicts the dough’s consistency and the final bread’s texture. Lower hydration (55โ65%) produces firm, easy-to-handle dough and denser bread. Higher hydration (75โ85%) produces sticky dough and open, airy crumb. The classification helps you anticipate handling difficulty and crumb structure.
Does the calculator account for flour type differences?
No. The calculator treats all flour as the same weight for calculation purposes. Whole wheat flour absorbs more water than white flour, so the same hydration will feel stiffer with whole wheat. Adjust your water upward when using significant whole wheat content.
Does the calculator store my recipe data?
No. All calculations run entirely in your browser. No personal or recipe data is saved or transmitted.
Can I share my sourdough calculations?
Yes. Use the Copy button to copy all results, or the Share button to send a summary that includes your hydration and dough weight.
Is this calculator a substitute for professional baking advice?
No. This tool provides mathematical calculations for home baking. For commercial production, recipe development, or troubleshooting, consult a professional baker or baking science reference.
How do I account for mix-ins like seeds, nuts, or dried fruit?
The calculator focuses on the core dough ingredientsโflour, water, salt, and starter. Add mix-ins to the total dough weight manually. Mix-ins do not affect hydration calculation but do affect dough handling and final weight.
