The majority of the potassium chloride produced is used for making fertilizer, since the growth of many plants is limited by their potassium intake.
As a chemical feedstock, it is used for the manufacture of potassium hydroxide and potassium metal.
It is also used in medicine, lethal injections, scientific applications, food processing, and as a sodium-free substitute for table salt (sodium chloride).
It is sometimes used in water as a completion fluid in petroleum and natural gas operations, as well as being an alternative to sodium chloride in household water softener units.
KCl is useful as a beta radiation source for calibration of radiation monitoring equipment