There are three types of salt used as flavoring agents in cooking, they include:

Despite the fact that many people believe that one salt may be more or less salty than another, this is actually a myth. Although there are many differences between kosher and sea salt, the salty taste of each is not one of them. This is actually the only similarity between the two types of salt.
In all actuality, all three types of salts - table salt, kosher salt and sea salt- contain the same amount of sodium, roughly 97.5%. All three salts are also recovered in the same way from salt mines. The differences, however, come in the additives that are added to each type of salt to give them difference in size, shape, and texture.
Kosher salt, while just as salty as sea salts, possesses some different and unique qualities when compared with its two counterparts. These qualities of kosher salt are that kosher salt:
Sea salt possesses different qualities than both kosher salt and table salt. These qualities include:
Since kosher salt and sea salt are equally salty, the choice to use one salt over another generally depends on what the salts are being used for.
In cooking, the salts will change the texture of your food, but not necessarily the taste. Therefore, when a recipe calls for kosher salt, but kosher salt is not available, you will need to use more of the sea salt to achieve the same texture.
In the case of curing or preserving meat, you will want to use kosher salt when available. If kosher salt is not available for use, you will need to use more of the sea salt to achieve the same as what the recipe calls for.