Calculator
Brine by grams per 100 mL of water
What most written recipes mean, and it is not the same number.
Result
50.0g salt
Working
Grams of salt per 100 mL of water, which is what most written recipes mean. salt = water volume x percent / 100 = 1000 mL x 5.00% / 100 = 50.0 g Taking 1 mL of water as 1 g, that brine is 4.76% salt by weight, not 5.00%. The difference grows with the strength of the brine.
Why this needs a calculator at all
Almost every recipe that says five percent brine means five grams of salt in a hundred millilitres of water. Taking a millilitre of water as a gram, that solution is 4.76 percent salt by weight, not five. The gap is small at five percent and large at twenty, which is exactly the range the FAO bulletin's brined products sit in.
What this is not
Arithmetic, not advice. It converts the number you type; it does not know what you are fermenting, how warm your kitchen is or whether your salt is pure. Nothing on this page certifies that a preparation is safe, and no result here should be read as a recommendation to ferment at any particular strength. The published parameters, with the sentence each came from, are on the tradition pages, and what can go wrong is on safety.