This article presents the implementation of an algorithm to calculate the volume and size of a database, where different ways to perform the mathematical operations that predict such size are shown in the Database Management Systems, PostgreSQL and Oracle. In order to optimize this process, a software is built that contributes to the decrease of the time used in the realization of calculations and manages to generate, in the user, a vision that helps in the analysis and making the right decisions that allow selecting the Hardware that must be implemented in the machine where the database is located. With the implementation of the algorithm can give a broader view of each of the tables, growth in size and volume of the database in real time.