Lacto-fermentation, measured.
Salt math for fermentation, solved.
Weigh your cabbage, pepper mash or cucumbers in grams, pick a salt percentage, get the exact salt mass. No sign-up. No ads until you finish the math.
Salt calculator
Enter your vegetable weight and a salt percentage. We return the exact salt mass in grams, plus teaspoons for each common grain.
Grain matters: one teaspoon of Diamond Crystal weighs half as much as one teaspoon of fine sea salt. Weigh in grams when you can.
All salt grains
| Grain | Grams | Teaspoons | Tablespoons |
|---|---|---|---|
| Diamond Crystal kosher | 20 g | 7.04 | 2.35 |
| Morton kosher | 20 g | 4.17 | 1.39 |
| Fine sea salt | 20 g | 3.51 | 1.17 |
| Pickling / canning | 20 g | 3.64 | 1.21 |
The gear that makes the math work
A short, honest kit for lacto-fermentation. The scale is the one that matters most — everything here is by weight.
- Digital kitchen scale (0.1 g)Salt % is by weight, not volume — a 0.1 g scale is what makes the math above accurate.View on Amazon →
- Glass fermentation weightsKeep vegetables submerged under the brine line so they ferment safely without mould.View on Amazon →
- Airlock fermentation lidsLet CO₂ escape while keeping oxygen out — wide-mouth lids that fit standard jars.View on Amazon →
- Wide-mouth mason jarsThe workhorse vessel for kraut, kimchi and brine pickles — 1 qt and ½ gal sizes.View on Amazon →
- Pickling / fine sea saltPure salt with no iodine or anti-caking agents, which can cloud brine and inhibit fermentation.View on Amazon →
- Stoneware fermentation crockFor scaling past the jar — a water-sealed crock for 5 L+ batches with built-in weights.View on Amazon →
As an Amazon Associate, Fermentcalc earns from qualifying purchases at no extra cost to you. More on how this is funded.
Our methodology
We weight salinity over time-and-temperature when sources conflict. Home fermenters control salinity reliably; kitchen temperature less so. Percentages are always by weight (salt mass ÷ vegetable mass, or salt mass ÷ water mass), never by volume — teaspoons of Diamond Crystal weigh almost half what teaspoons of fine sea salt do, which is the most common cause of failed ferments. The 1.5% floor for dry-salt ferments and the 2.5% floor for submerged brines are enforced as safety verdicts, not hidden as warnings.
Data we cite on every page
Fermentcalc builds on the National Center for Home Food Preservation (NCHFP), the FDA pH-safety threshold (4.6), USDA canning guidance, Sandor Katz’s Wild Fermentation and Art of Fermentation, the Noma Guide to Fermentation by René Redzepi and David Zilber, and the Joy of Pickling by Linda Ziedrich. Every data-backed page names a source and a last-verified date.