Time estimation is important can be used to organize and structure all projects. Using good time estimation techniques may save time, and money. First, project manager should familiar with the task to be carried out and understand the project outcomes well; this might be one of the reason that team can underestimate the time duration if project manager not knowing the project well enough. Project manager can breaks large tasks down into detailed tasks and well explained to the team members so they know inside out of the project in details. Project manager should ask for progress report from team members at least on weekly bases. Lastly, always prepare for project to go wrong due to expected and unexpected disruptions and delays to work that will inevitably happen. Project manager allows some extra time for any urgency tasks such as missed deliveries by suppliers, quality control rejections, breakdown in equipment, and meetings.