Purpose: A robust method in environmental load assessment of buildings is urgently required to reduce the environmental burden of the construction industry. While the industry utilizes the life cycle assessment (LCA) method to assess environmental impacts of detailed designs, the implementation of changes at that late stage of development is often expensive and undesirable. On the other hand, during the early design stages, the LCA method is severely limited by the lack of information available, e.g., uncertainty about final materials to be used. This research study investigates how building information modeling (BIM) can facilitate LCA analysis at an early design stage. Design/methodology/approach: A literature review is conducted to establish a framework for BIM and LCA integration, which creates the foundation for the development of a new BIM-based LCA tool. The tool is empirically evaluated on a large case study of a residential building in Denmark. Findings: Case study results show that the new tool facilitates decision-making in an integrated design process, providing reliable LCA results on an early stage model, while avoiding intermediate manual input by the end user in contrast to other commercial LCA tools. Originality/value: A first prototype of a BIM-based tool is demonstrated, which allows professionals, small architectural companies, students and researchers to calculate the environmental loads of the building in the early design stage in an automated, transparent and time-saving manner.