Quantity estimation is a critical component of construction project planning, particularly in public-sector building projects, where accuracy, efficiency, and transparency are essential. In the Department of Public Works and Highways (DPWH), quantity estimation supports cost and scope determination and project approval. Despite generally acceptable performance, inefficiencies persist due to the absence of standardized digital workflows and the adoption of optimized process software for estimation. This study assessed the impact of quantity estimation practices on DPWH Engineering Districts’ building projects in Laguna. It examined the relationship between respondents’ profiles and the extent of impact on project scope, cost accuracy, and time. A descriptive research design was employed using survey questionnaires administered to licensed civil engineers in the Planning Section of DPWH. Descriptive statistics and Spearman’s rho correlation were used for data analysis. Findings show that current practices are adequate but can be improved in terms of efficiency, consistency, and workflow integration. A significant relationship between estimation practices and project planning effectiveness was identified. A Quantity Estimation Standardization Plan was developed to support improved planning performance in public infrastructure projects.

Keywords: digital workflow standardization, quantity estimation, estimation software adoption, dpwh engineering districts, public infrastructure