Sourdough Starter Calaculator
Quickly calculate how much flour, water, and starter you need—no guesswork.
If you’re new to sourdough baking (or just tired of doing mental math before your coffee), this simple calculator helps you build the exact amount of active sourdough starter for any recipe. Whether you need 100g or 250g, just plug in how much seed starter you’re using, and we’ll tell you how much flour and water to add. Done and dusted.
Why use a sourdough starter calculator?
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Ensures your starter is at 100% hydration
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Helps reduce waste by only making what you need
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Great for planning ahead for bakes, whether you're making one loaf or four
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Beginner-friendly, perfect for home bakers getting started with sourdough
What is 100% hydration starter?
Most sourdough recipes call for a starter that’s fed with equal parts flour and water by weight. That’s what this calculator is built for—so your starter will always rise like it’s supposed to.