The American Chemical Society Green Chemistry Institute Pharmaceutical Roundtable has utilized process mass intensity (PMI) as the key high-level metric to evaluate and benchmark progress towards more sustainable manufacturing. The long-term aim is to move towards metrics based on life cycle assessment (LCA) methodologies. This paper describes the development of a streamlined PMI and LCA tool intended to be used as the standard early assessment of synthetic routes for active pharmaceutical ingredients (API) and fine chemicals, especially during the route development stages when life cycle inventory data are often not readily available.