From June 11 to 14 in the city of Orlando, Florida, the AACE International 2017 Annual Meeting will be held, an annual meeting that provides the opportunity to expand knowledge in Project Control. Anddes will be present with a paper: “Estimation of Cost Variability at different levels of project definition”, prepared by our Cost and Budget Engineers, Franco Sanchez and Edisson Pérez. The article prepared deals with the estimation of the cost of a project carried out according to the level of engineering developed, it mentions that while in this a greater definition of engineering is carried out, the estimation of the cost of the project will have greater accuracy. That is why it is important to ask ourselves about what is the range of accuracy of the estimate of the cost of a project for each level of engineering. For the development of this article, the estimated costs of different projects developed in the mining sector were used and the variability of the cost was analyzed as these projects advanced through the different levels of project definition. As a result of the analysis, the range of accuracy that the project costs had was obtained according to each level of engineering developed, which may serve as a reference for future projects, and the trends will be interpreted to reach a better cost management for similar projects.