摘要:Objective. The rural diversification is a way for family farmers to prosper or even to perish. However, deciding a new rural activity can become hard work. The objective of this work is creating an Information System that helps the farmer in decision making, through financial indicators. Method. A questionnaire was applied to 20 family farmers of Oeste Paranaense with a quantitative approach, and a bibliographical and documentary research was carried out to verify Information Systems available. Subsequently, a software project was developed using UML elements and the ASP.NET Core MVC 1.1 development framework with PostgreSQL 9.5 database. The IDE used for development was the Microsoft Visual Studio 2015 Community Edition. The tests were performed in a Linux environment with Ubuntu 14.04, Apache 2, and Chrome 55 browser. Results. The implementation of the software project resulted in the nominated application of Rural Financial Planning (Plafir). Plafir is a web application that assists in decision making when the farmer decides to invest in a new rural activity. Based on financial models pre-registered in the system by agricultural technicians, and a table of inputs with updated prices, the farmer can select a particular model, simulate the production, and check the financial results. Conclusions. Family farming is lacking Information Systems for decision making, and the application Plafir meets the objective proposed in this study, contributing to the decision making of a new rural activity.