According to WritingExplained.org, “preventive” and “preventative” are interchangeable. They can both be used as a noun or an adjective. The words both “refer to things that prevent, hinder, or act as obstacles.”

WritingExplained.org further explains that between the two word choices, internationally, “preventive” is the preferred choice; being used approximately eight times more than “preventative.”

The website also states that the existence of the word “preventive” predates “preventative” by a few decades, and is preferred by the New York Times, AP Stylebook, The Chicago Manual of Style, and other grammar sources.