One formula: water grams × % = grams of salt. Weigh it, don't scoop it.
Live calculator · updates as you type
Set your brine
L
Common targets
3.5%
0.5%5%10%
Weigh out
Salt to weigh35g
Tablespoons1.9
Teaspoons5.8
Ounces1.23
About as salty as seawater — the standard vegetable-ferment band.
For your brine
Water1.00 L
Salt35 g (~1.9 tbsp)
Target3.5%
Salt-type note
fine sea salt runs about 18 g per tablespoon. Because volume varies so much between salts, the gram weight is the only figure that travels safely between recipes.
Use non-iodised salt — iodine and anti-caking agents can interfere with fermentation.
How to mix it
Weigh the salt, then stir it into the measured water until fully dissolved. Warm water dissolves salt faster — cool the brine to room temperature before pouring it over vegetables.
Estimates assume water at about 1 g per ml. Percentages are by weight of the water.
Quick anchors
3.5% is the seawater-strength workhorse for vegetable pickles. Go lower for kraut, higher for long-keep pickles and brined cheeses.
1 L + 2% → 20 g · 1 L + 3.5% → 35 g · 1 L + 5% → 50 g (fine sea).
Salt percentage chart
Salt %Per 1 LBest forTaste
2%20 gSauerkraut, kraut-style fermentsMilder than seawater
2.5%25 gKimchi, hot-sauce mashJust under seawater
3.5%35 gCucumber & most vegetable picklesSeawater-salty
5%50 gLong-keep pickles, feta brineSaltier than seawater
10%100 gOlives, long brining cyclesVery salty
Percentages are by weight of the water. For sauerkraut and kimchi, salt is usually calculated against the vegetable weight instead — use the fermentation brine calculator for that dry-salting method.
Salt brine guide
One formula covers every brine.
Use the calculator above for the grams. Use the guide below to pick the right percentage, understand why weighing beats measuring, and know when to salt by vegetable weight instead.
Kraut-style2%
Milder than seawater — lively and quicker to sour.
Vegetable pickles3.5%
Seawater strength — the workhorse band for most ferments.
Long-keep & feta5%
Saltier than seawater, for slow brines and brined cheese.
Salt brine formulawater g × salt % = g salt
1000 g water × 3.5% = 35 g salt. Because water is about 1 g per ml, a litre is roughly 1000 g, so the maths stays simple at any volume.
01
How to calculate salt for a brine
A salt brine percentage is simply the weight of salt as a share of the weight of the water. Since water weighs about a gram per millilitre, a litre of water is roughly 1000 grams, and a 3.5% brine needs 1000 multiplied by 0.035, or 35 grams of salt. That single calculation covers every brine you will ever mix; the only things that change are the percentage and the volume.
The calculator above does the arithmetic for any water volume in litres, quarts, or cups, and any percentage from a mild 2% to a heavy 10%. It also converts the result into tablespoons for whichever salt you select, so you get both the precise gram weight and a rough volume to sanity-check against.
Fast anchors (1 L water)
2% → 20 g salt3.5% → 35 g salt (seawater strength)5% → 50 g salt
02
What percentage for which ferment
Most vegetable fermentation lives between 2 and 3.5%. Sauerkraut and kimchi sit at the lower end, around 2 to 2.5%, which keeps them lively and lets them sour fairly quickly. Cucumber and most vegetable pickles use around 3.5%, the strength of seawater, which protects crunch through a longer ferment. Long-keep pickles and brined cheeses like feta step up to about 5%.
Higher percentages slow fermentation and favour salt-tolerant bacteria, which is exactly what you want for long brining cycles and olives, sometimes 8 to 10% or more. Lower percentages ferment faster but leave less margin for error, so a cool room and clean handling matter more. Pick the band for your vegetable and let the calculator set the grams.
2%Sauerkraut and kraut-style ferments — milder than seawater.
2.5%Kimchi and hot-sauce mash.
3.5%Cucumbers and most vegetable pickles — seawater strength.
5%Long-keep pickles and feta brine — saltier than seawater.
8–10%Olives and long brining cycles.
03The one rule
Why you should weigh salt, not measure it
Salt is the one ingredient where volume measurements quietly betray you. A tablespoon of dense fine sea salt can weigh more than double a tablespoon of flaky Diamond Crystal kosher salt. Follow a recipe written for one salt using a scoop of the other, and your brine can end up half as strong or twice as strong as intended.
Weighing in grams removes the guesswork entirely. Whatever salt you have, the gram figure gives the same brine strength every time. The calculator still shows tablespoons as a convenience, but treat that as a rough check and trust the scale — it is the number that travels safely between recipes and salt brands.
04
Which salt to use
Use non-iodised salt for fermentation. Iodine can inhibit the beneficial lactobacillus, and the anti-caking agents in many table salts can cloud the brine. Fine sea salt, pickling or canning salt, and pure kosher salts (Diamond Crystal, Morton) are all good choices. Himalayan pink and other pure mineral salts work fine too.
The differences between these are mostly about density and dissolving speed, not fermentation outcome. Pick one you can buy consistently and get to know its weight per tablespoon. The calculator carries densities for the common types so the volume conversion stays honest when you switch between them.
05
Percentage of water, or of everything?
There are two conventions, and mixing them up is a common source of confusion. The most common home method, and the one this calculator uses, bases the percentage on the weight of the brine water alone. It is simple and works well for submerged-vegetable ferments where you pour a measured brine over the produce.
The other convention bases the percentage on the combined weight of the water and the vegetables. It is more precise for tightly packed jars, since the vegetables release their own water into the brine. If your recipe specifies total weight, simply add the vegetable weight to the water weight before you calculate, and the grams the tool returns will match.
06
When to salt by vegetable weight instead
Not every ferment uses a poured brine. Sauerkraut, kimchi, and other shredded-vegetable ferments are usually dry-salted: you weigh the vegetables, calculate a percentage of that weight (commonly 2%), and massage the salt directly into them until they release their own brine. No added water is involved.
For that method, this water-based calculator is not the right tool — use the fermentation brine calculator, which has a dry-salting mode keyed to vegetable weight. A good rule of thumb: if you pour liquid over the vegetables, calculate against the water here; if you rub salt into the vegetables, calculate against their weight there.
07
Mixing and using the brine
Weigh the salt, then stir it into the measured water until it fully dissolves. Warm or hot water dissolves salt much faster, which is handy for heavier brines, but cool the brine back to room temperature before pouring it over vegetables so you do not shock the ferment or soften the produce.
Pour enough brine to submerge everything completely, and use a weight to keep the vegetables under the surface. Anything poking above the brine is where mould and kahm yeast take hold. A little extra brine mixed at the same percentage is worth having on hand to top up jars as the ferment settles.
08
Getting the strength right for safety
Salt does more than season a ferment — it steers which microbes thrive. Enough salt suppresses spoilage organisms while the lactobacillus get going, which is why undersalting is riskier than a slightly heavy hand. If you are unsure, staying within the standard 2 to 3.5% band for vegetables gives a reliable, safe ferment.
Cloudy brine and a sour smell are normal signs of a healthy ferment. Slimy textures, off or putrid odours, or coloured fuzzy mould are not, and mean you should discard the batch. When precision matters, weigh both the salt and the water, and lean on tested recipes rather than eyeballing the scoop.
Download the free Brine & Pickling Reference Card
One printable reference card — salt percentages by ferment, per-litre gram anchors, and salt-type density conversions.
Quick answers on salt percentages, weighing versus measuring, and which salt to use.
How do I calculate the grams of salt for a brine?
Multiply the water weight by the salt percentage. For a 3.5% brine with 1 litre of water (1000 g), that is 1000 × 0.035 = 35 grams of salt. The calculator does this for any percentage, water volume, and salt type.
What salt percentage should I use?
For lacto-fermenting vegetables, 2 to 3.5% by weight of the water is standard. Sauerkraut and kimchi sit around 2 to 2.5%, most vegetable pickles around 3.5% (seawater strength), and long-keep pickles or feta brine around 5%. Olives go higher still.
Why weigh salt instead of measuring by volume?
Different salts have very different densities. A tablespoon of fine sea salt can weigh more than twice a tablespoon of flaky Diamond Crystal kosher salt. Weighing in grams removes that error, so your brine strength is consistent no matter which salt you own.
Should I use table salt for brining?
Avoid iodised table salt and salts with anti-caking agents — iodine can inhibit the beneficial bacteria in fermentation and additives can cloud the brine. Use non-iodised salt: fine sea salt, pickling salt, or any pure kosher salt.
Is brine percentage based on water weight or total weight?
This calculator bases the percentage on the weight of the water, which is the most common home-brining convention. Some recipes base it on the combined weight of water plus vegetables; if yours does, add the vegetable weight to the water figure before calculating.
How much salt is in a 5% brine?
A 5% brine has 50 grams of salt per litre of water. That is saltier than seawater and suited to long-keep pickles and brined cheeses like feta. Use the calculator to scale it to your exact vessel volume.
