Simulation is becoming more important nowadays, where there is a need for developing or improving projects more efficiently without taking any economic risk. Jernbro Industrial Services AB in Skövde is specialized in Automated Guided Vehicles (AGVs) production, and so far, they have been calculating the optimal number of AGVs of a system by using Excel. However, they want to go a step further and include simulation in their projects to obtain this data more accurately and efficiently and update their working procedures. In this thesis, former articles and researches have been studied to acquire knowledge in previous works related to the calculation of the optimal number of AGVs. A market survey has been conducted to find the best software simulation tool in the market for AGVs, by analysing the main features of each software. Although many software satisfies the requirements, FlexSim is the tool that has been chosen, as it provides good results in a user-friendly way. Therefore, in order to validate whether simulation provides accurate and interesting data for the company, an already existing model has been simulated to compare the new results with the former ones calculated with Excel. After discussing the results and the issues that have been confronted during the project, it has been found that the optimal number of AGVs in the system is 3 but, in view of security and the unpredictable behaviour of AGVs systems, 4 is the number considered as the best solution for the model. Moreover, all the benefits of simulation are presented as a solution for future projects the company develops.