Construction projects are naturally tied up in contract agreements between parties involved in completing all the work that is contained in the contract. However, projects often go beyond their allocated time for various reasons. This study is carried out on Bahir Dar public construction projects to make a contract time determination for public building projects in general and to investigate factors affecting contract time during the construction phase. To achieve the objective of this research, a desk study, survey questionnaires, and case studies were carried out on selected projects. The study revealed that some consultant organizations have standard procedures to determine contract time, using empirical formulas that consider project costs and factors that affect contract time. An analysis of linear regression models was developed to predict the new productivity rate for the selected critical civil work activities by using the data obtained from contractors’ organizations, and case studies were selected to estimate the duration of each critical activity. Next, the duration was entered into Microsoft Project, which schedules the project to determine contract time as a number of working days. According to the findings, realistic contract times are not drawn from the practices and methods that are used to determine contract times. The clients and respective consultant organizations of building projects should give realistic and reasonable contract times for contractors.