Parametric cost estimates are prepared at conceiving phase of a construction project life where drawings and specifications are not obtainable. Despite their low level of accuracy, they are used at feasibility study based on previously executed projects after necessary adjustments are performed. At this stage, precise and reliable historical cost data, either published or from the industry, has to be available for cost engineers and estimators. Ever since the construction industry has adopted the application of Management Information Systems (MIS) through the relevance of databases, its' construction processes has been widely enhanced by means of eliminating emissions, errors, cost and time reduction. Thus, this paper describes the development of a model that automates the preparation of parametric cost estimates for building projects based on Assembly and Masterformat work breakdown structure in both metric and imperial units after effecting all required adjustments. This would provide cost engineers and estimators with a vital tool that reduces cost and time, minimizes human errors and emissions and generates various types of output reports.