Production of wet crude due to the raise in oil-water contact in many oil fields has been a growing field problem and consequently production of salty wet crude affects the quality of crudes. In this work, a simple computer program using Arrhenius-type function and Vandermonde matrix is presented for estimation of formation water properties for temperatures above 30°C and salt contents between 5 and 25 percent by mass. An Arrhenius type function has been selected because it is easier than existing approaches, less complicated with fewer computations and suitable for engineers. These expressions have been programmed using Matlab computational technical language and it can then be incorporated into further calculations that require predictions of formation water properties as functions of temperature and salt content. Estimations are found to be in excellent agreement with the reliable data in the literature with average absolute deviation varying between 0.08 to 2.7 %. The method developed in this study is of immense practical value for petroleum engineers and practice engineers for a quick check on the formation water properties at various conditions without opting for any experimental measurements. In particular, chemical and petroleum engineers would find the proposed approach to be user-friendly with transparent calculations involving no complex expressions.