The cost level is a very important factor in most construction decisions, and its estimates are prepared during the planning, design and construction phases of a construction project. Various types of cost estimates are made in a construction project, from preliminary estimates to detailed estimates. All these estimates are important because they invariably influence the expenditure of major expenses. Estimates made in the early stages of a project are of particular importance, as they influence the most basic decisions related to the construction project. Cost estimation can be defined in various ways. For example, estimation is the assembly of all the costs of the elements of a project, which for an entrepreneur represents the cost that will most likely be incurred for the completion of the project. In another definition, it is a statement-making about the approximate amount of materials, time, and costs to take construction decisions. Cost estimation is also defined as the process of analyzing a specific work and predicting the cost of performing it. The main challenges facing the construction contractor are estimating the cost of building a project, scheduling specific construction activities, and then building the project within the estimated cost and schedule. Source: Rahul kumar