🧪 Free Fermentation Calculators
Precision tools for
home fermenters
Exact ratios for sourdough, mead & kombucha — calculated instantly, completely free.
Choose your fermentation
Three fermentation hubs. All the calculators you need.
How it works
Precise results in under 30 seconds.
Enter your inputs
Batch size, target hydration, or gravity reading — whatever your recipe calls for.
Get instant results
Exact weights, ratios, and timings — calculated in real time as you type.
Download your log
Free printable PDFs on every calculator page — feeding logs, batch trackers, reference cards.
Frequently Asked Questions
About Ferment Calculator
Are all the calculators free?
Yes — every calculator on Ferment Calculator is completely free to use, with no signup required. We offer optional free PDF downloads (email required) and paid printable journals in our shop.
What fermentation types do you cover?
We currently cover sourdough, mead, and kombucha — with more fermentation types coming soon. Each vertical has its own dedicated hub with multiple calculators, free guides, and a quiz.
How accurate are the fermentation calculators?
Our calculators use the same formulae used by professional bakers, commercial meaderies, and fermentation scientists. Sourdough hydration uses baker's percentages; mead ABV uses standard OG/FG calculations; kombucha uses verified sugar-to-tea ratios.
Can I use these calculators on mobile?
Yes — all calculators are fully responsive and work on any device. No app download needed.
Start calculating — it's free
No signup. No ads tracking your inputs. Just accurate fermentation maths.