Purpose: The purpose of the paper is to marshal the carbon sources, and explore a computational model to calculate the buildings’ carbon emissions by using building information modeling (BIM) techniques. The study aims to integrate the BIM techniques with the carbon emission and energy analysis tools, which can provide a more exact quantification result.Design/methodology/approach: To define the scope of this study, several standards or regulations have been comparatively analyzed. The BIM technique has also been used to establish the computational model of carbon emissions, including the calculation principle, the basic database, and each process of modeling. Finally, a case study is given to test the theoretical study.Findings: The paper provides a quantitative calculation method for the carbon emissions of buildings, and suggests an approach to integrate the BIM techniques with the low carbon research. This allows the quantity of material consumption and carbon emission to be calculated in real time during the whole construction process.Research limitations/implications: Because of the chosen American database, the calculation results may lack generalizability. Therefore, the approach of establishing a universal database of carbon emission coefficients will be the next key point.Practical implications: As this research shows, there is a need for an advanced calculation method to evaluate the buildings’ carbon emission exactly by BIM techniques, which also provides a basis to establish the regulation of carbon transaction tax in the future.Originality/value: This paper fulfils an identified need to calculate the carbon emission during the buildings’ construction stage, so that better decisions can be made to optimize the construction plan and choose the low emission materials properly.