Fermentation calculators that just work
Free, no-signup calculators for brine, kombucha, sourdough, beer and more. Every formula explained, every reference number sourced.
Every calculator organized by ferment - pick your project and get exact numbers in seconds.
Homebrewing Beer 
- Priming Sugar Calculator
- Hydrometer Temperature Correction
- Brix to SG Calculator
- Strike Water Temperature Calculator
- Mash Efficiency Calculator
- ABV Calculator
- IBU Calculator (Tinseth)
- Force Carbonation Calculator
- Yeast Pitching Rate Calculator
- Beer Calorie Calculator
- Brewing Water Calculator
- Beer Color Calculator
- Attenuation Calculator
Kombucha 
Sourdough Baking 
Pickles & Brine 
Yogurt & Dairy 
Mead & Cider 
Fermented Condiments 
General Tools
Guides
Browse all guides
Experiments
Play, and log what happens. Each entry is a short, hands-on protocol - what you need, what to watch for and which calculator does the arithmetic - written so you can run it in your own kitchen. Start any experiment from its page and it shows up on your bench below. New entries land at the top as the log grows.
Why FermentCalc
Most fermentation calculators hide the math. Here every tool shows the formula it uses, links the source of every reference value, and works offline once loaded. No accounts, no paywalls.
Free and no-signup
No accounts, no paywalls. Calculations run in your browser and never leave your device.
Sourced numbers
Reference values cite published recipes, extension guidance and primary literature - so you can check the basis of every number.
Formulas explained
Each tool comes with a plain-language guide covering the formula, the units and the common mistakes.