A simple and easily programmed code is proposed for estimating the scaling potential for different scaling species, that are expected to be precipitated in reverse osmosis (RO) systems, as calcium carbonate, calcium sulfate, barium sulfate, calcium fluoride and strontium sulfate scaling. All types of scaling in RO system will be included in the simple code calculation, especially when Gulf Seawater or brackish water is the feed to system. All what is required is to enter the chemical composition of the feed water and estimate the conversion, and then the program will determine if there is any chance for scaling problem at the proposed the conversion. Also the program can help in optimization to choose the correct conversion without risk of scaling, and thus make it possible to increase to increase this conversion using acid treatment method. The paper also compared between the equations that have been used in the simple code and other equations used by other authors in the literature survey, the program has been tested in Kuwait Doha research plant and proved its reliability and availability in estimation the potential for scaling for different RO units of. This code can be consider as an important tool for all RO operators all over the world.