The following calculator will help you create a starter or levain to meet a recipe’s requirements. For instance, with this calculator, you can create any size of levain if you know the hydration percentage (the amount of water to total flour) and the amount of ripe sourdough starter to add (the inoculation).
If you haven’t yet worked with baker’s percentages, which this calculator uses, review my introductory guide to baker’s percentages.
Example Calculation
Let’s look at a quick example. Let’s say you have a recipe that needs 100 grams of ripe sourdough starter. The recipe also says the starter should be at 100% hydration (equal water and flour) and is made with a 50% seed (the amount of ripe starter you add). By the way, a build like this will usually ripen in 5-6 hours at about 78°F (26°C).
Using the calculator below, starting from the top, plug in the end desired starter weight (100g), the desired hydration (100%), and the ripe starter to add (50g).
The desired starter can be made by mixing the outputs below in the grey boxes (50g starter, 25g flour, 25g water).
Starter and Levain Calculator
Have questions or need help with the calculator? Feel free to email me on the About page.
What’s Next?
Need to know what temperature to warm your mixing water to achieve a particular dough temp? Use my mixing water temperature calculator to do exactly that! This way, your dough will ferment on schedule and according to any recipe you’re following.
