Your best bet: Kosher salt
One of the big differences that you will find between pickling salt and kosher salt is the size of the grains. Kosher
This means that you will need to adjust the quantity of kosher salt when you use it as a substitute. Some cooks recommend formulas such as increasing the amount of salt in a recipe by 50 percent. A simpler way is to measure by weight when making this substitution.
A decent second choice: Sea salt
You can use sea salt as a pickling salt substitute. It should work since it has none of the additives that make other salts less than ideal; however, note that some sea salts will have more of some minerals than others.
In a pinch: Non-iodized table salt
Salt without iodine is missing the big thing that pickle experts say most affects the flavor and color of pickles. Table salt without iodine does not cause those problems and therefore provides the same benefits as pickling salt. Also good is the fact that the grains are relatively small,
Iodized table salt is the most controversial and vilified salt when it comes to pickling; however, it will serve the same purpose as pickling salt if you have no other alternatives. While some say that it affects flavor negatively and darkens the color of pickles, it is still safe to use and will get the job done.