This article describes the development of a program in Matlab to automate the calculations of operating costs of fleets of electric buses as a study prior to the replacement of a fleet of diesel buses. The program estimates the electrical consumption of buses on specific itineraries and optimizes load management, allowing compliance with the regular operating program with the lowest possible operating cost. This is achieved through the adaptation and processing of real data provided by a diesel bus company. A program was developed in Fico Xpress that uses ANDE's tariff schedule to reduce power and energy contracting costs. The itinerary measurements made with GPS, previous data processing and physical modeling of an electric bus in Simulink make it possible to predict the energy consumption of the bus and determine the operational feasibility in the study itinerary for a typical week of operation. Before converting a fleet from diesel buses to electric, it is crucial to know this information to predict whether the specific bus model meets the necessary technical requirements. Furthermore, since it is an automated program, it is enough to alter some input parameters to analyze the performance of various bus models or itineraries and determine the minimum operating cost for each configuration.