Quick Summary: This free sourdough calculator builds your bread formula using baker's percentages. Enter your total flour weight, then set the hydration, salt, and starter percentages, and it instantly returns the exact grams of flour, water, levain, and salt, along with your total dough weight and true total hydration.
To find hydration yourself, divide water by flour and multiply by 100 (for example, 350g water ÷ 500g flour × 100 = 70%).
Sourdough calculator
What is a sourdough calculator?
A sourdough calculator is a tool for creating a bread formula using baker's percentages.
But unlike most sourdough calculators out there, this one does more than just basic math. It lets you:
- Blend flours: Calculate the exact weight of each flour in your custom mix.
- Adjust hydration: Set your ideal dough hydration with precision.
- Plan your levain: Calculate the amount of levain/active starter you need based on your feeding ratios.
- Account for losses: Adjust levain/active starter weight to cover the bit lost when transferring between jars.
- Total dough weight: Instantly see how much dough you will make.
- Total hydration: This includes the water already in your starter, giving you true total hydration (see my guide on sourdough hydration)
How to use the sourdough calculator (step-by-step)
1. Set your flour base
- Enter the desired total flour weight in grams at the top.
- Adjust the individual flour percentages to create your custom mix. Make sure the total flour equals 100%.
2. Choose your hydration and salt
- Set your preferred hydration level. If you are new to sourdough, don't exceed 70% hydration.
- Adjust salt percentage as needed. 2% is a standard starting point.
3. Customize your starter (levain)
- Enter the percentage of levain/active starter you plan to use. Most recipes use around 20%.
- By default, the calculator uses the starter at 100% hydration (equal parts water and flour).
- Use the feeding ratio section to adjust the flour ratio. The water ratio will automatically match the flour to keep the starter at 100% hydration.
Bonus: The calculator also calculates adjusted weights, with an extra 10% to cover transfer losses when moving your starter between containers.
4. Review your results
Once your numbers are set, scroll down to view the calculated results, including:
- Total dough weight: The final weight of your dough, shown in grams.
- Total hydration: The overall hydration level, including water from both the dough and your levain/active starter, shown as a percentage.
- Bread formula: A full, clear breakdown of all ingredients, measured in grams.
All numbers update instantly as you change values, so you can experiment freely and see results in real time.
If you want to use the adjusted weights for the levain ingredients (which include an extra 10% to account for transfer loss), refer to the calculation above.
Real-life example
Let's say you want to make a single loaf using:
- 500g flour
- 70% hydration
- 20% levain/active starter
- 2% salt
Here is what the calculator gives you:
- Total dough weight: 960g
- Total hydration: 72.7%
- Bread flour: 500g
- Water: 350g
- Levain/active starter: 100g
- Salt: 10g
If you need to bake 3 loaves, change the flour amount. The calculator will handle the math. Also, read how to scale a sourdough bread recipe.
Save the calculator for later
Want quick access every time you bake? Save the sourdough calculator to your phone's home screen:
- iPhone: follow the steps in this video.
- Android: watch this video.
You can also pin it on Pinterest to find it again later.
Common beginner mistakes (and how to avoid them)
- Forgetting to include the starter's water and flour: Remember, a 100% hydration starter is made with equal parts of flour and water. The calculator takes this into account. There is no need to manually subtract or adjust.
- Misunderstanding percentages: Baker's percentages are always based on the total flour, which is always 100%. So, 70% hydration means 70% of the flour weight, not the total dough weight.
- Trying to eyeball it: Accurate baking starts with a kitchen scale. Even small measurement errors in hydration can change the final texture of your loaf.
FAQ
What is the difference between dough hydration and total hydration? Dough hydration counts only the water you add. Total hydration also includes the water already in your starter, so it is the more accurate figure.
How much starter or levain should I use? Around 20% of the total flour weight is standard, and this is your inoculation percentage. For 500g of flour, use about 100g of levain. Less slows fermentation; more speeds it up. Learn more in my guide to inoculation percentage.
What hydration should a beginner use? Stay between 65% and 70%. Lower hydration dough is firmer and much easier to shape while you learn.
What is the standard salt percentage? 2% of the total flour weight is the standard starting point.
Ready to bake?
Scroll back up to the calculator, plug in your numbers, and start building your sourdough bread recipe. If you are not sure where to begin, try this Beginner's Sourdough Bread recipe.
And if you have not yet created a starter, this easy sourdough starter recipe will walk you through making it from scratch.
Ready to keep learning?
If you are following along from one blog post to the next, calculator in hand, you might wonder what makes sourdough truly perfect. Discover the key elements that create the perfect sourdough bread.