The paper presents a verification of whether how much the Unity environment scales in simulations. It will allow us to check whether Unity, as a free program and a game engine, will allow for carrying out larger simulations. The case presented uses a model of a public building, where a simulation of evacuation in case of fire was realized. Under normal conditions, evacuation of about 100 people is assumed, while the upper limit for which the simulation performed correctly is a maximum of 20,000 people, which allowed verification of the scalability of the developed solution. In the course of the study, RAM occupancy and simulation stability were measured.