If in a project there are different estimates, at first the project manager should ground all the estimates, by grounding all the estimates project manager will get a better information and can use all the estimates according to their requirements. Accurate estimating for all the projects on all sizes is a big deal to all the project managers. All the previous projects and estimating techniques of the company will help the project managers to make the decisions accurate. Project stake holders and team members who are particular to that departments can help the project managers to produce Accurate estimation for the projects.