Assessing the human impacts on biodiversity is important for conserving biodiversity. Life cycle assessment (LCA) is a tool to assess the impact product service systems have on the environment. To critically asses the human impact of land use on biodiversity in LCA, characterisation factors (CF) are needed to translate area and type of land use into loss of biodiversity. Most CFs are based on species richness but another biodiversity indicator, functional diversity (FD), better represents ecosystem functioning compared to taxonomic measures such as species richness. This study proposes a new method for calculating CFs, based on FD, for assessing impact of land use on plant biodiversity. To demonstrate the applicability of the method that is proposed, CFs were calculated based on data from Germany. The data was divided into four types, being land use, plant abundance, trait data and environmental data. The CFs developed show trends in impact on biodiversity in accordance with other studies. The proposed method in this study can guide in the development of more precise and geographically diverse CFs for assessing the impact of land use in biodiversity in LCA.