An Estimator plays a vital role in project planning by assessing costs and resource requirements, ensuring accurate budgets and competitive bids. Key responsibilities include analyzing project specifications, preparing detailed cost estimates, and collaborating with engineers and project managers. Required skills include analytical thinking, attention to detail, and proficiency in estimating software. Estimators typically work in construction, engineering, or manufacturing environments. Career progression may lead to roles such as Senior Estimator, Cost Manager, or Project Manager, offering growth in responsibility and strategic influence within the organization.