Industry and scientists develop new nanomaterials and nano-enabled products to make use of the specific properties that the nanoscale can bring. However, the benefit of a nano-enabled product over a conventional product is not always a given. This paper describes our development of a Benefit Assessment Matrix (BAM) that focuses on the functional, health and environmental benefits of nanomaterials, nano-enabled manufacturing and nano-enabled products. The BAM is an Excel spreadsheet-based tool to help researchers and small and medium-sized enterprises assess these potential benefits throughout their product’s life cycle while they are still in the early phase of the innovation process. Benefit indicators were developed based on a review of the literature on the life cycles and intrinsic properties of nanomaterials, nano-enabled manufacturing and nano-enabled products. Assessing the benefits of a nano-enabled product involves a comparative approach, contrasting them against the benefits of a conventional reference product. To help users understand the reliability of the benefits, the BAM identifies the evidence of the benefit claimed. The BAM provides a different action plan for each phase of the stage–gate product innovation process. The tool’s applications and potential are presented using three case studies, focusing at different phases of the innovation process: nano-clays used in internal automobile body-panels, nano-TiO2 used in outdoor facade coatings and nano-Ag used in T-shirts. Using these cases studied, we highlight how the results from the BAM can be used to give recommendations for moving towards the concept of safe and sustainable by design in nanotechnology development.