Given the ambitious climate reduction targets of the European Commission for the building sector and the adoption of the life cycle assessment method for the environmental metrics, the authors of this research present a new tool that allows for an extensive evaluation of buildings (operational and embodied environmental profile). The tool developed is an engine written in Python that was applied to analyze the buildings of Milan, using several open databases available for the Lombardy region (Northern Italy). Approximately 240,000 building units were investigated and compared using ecoinvent 3.9.1 EN 15804 as a background library and characterization methods in compliance with EN 15978. The tool can establish reliable environmental benchmarks to implement building policies, such as climate footprint limits for new constructions as required by the recast Energy Performance of Buildings Directive (2023). This article shows the embodied impact of construction materials. The results for residential, commercial, and retail building units (old and new) are 15 kg CO2eq/(m2 of net area × year) for the entire building stock (old and new building units) and 21 kg CO2eq/(m2 of net area × year) for new buildings (nearly zero energy building units).