Background: Only a few decades ago, colorful, small-scale, heterogeneous, and species-rich hay meadows or extensive pastures were common, but have often been replaced by species-poor, uniform, large-scale multicut meadows. Technological advancements and improved efficiency in grassland management have come at the cost of biodiversity. Methods: In Germany, 150 grassland plots have been investigated since 2006. Using these extensive data, we propose a new compound index for estimating the site-specific mowing intensity in order to facilitate assessment of the impact of mowing intensity on biodiversity and ecosystem processes. Our index integrates the various qualitative components of mowing machine type, mowing height and use of a conditioner, with the annual number of cuts. Results: The newly proposed index achieves a much finer gradation of mowing intensity compared to the previous quantification based on the number of cuts only. Furthermore, a decrease in plant and arthropod species was observed at higher mowing intensity. Conclusions: The proposed mowing intensity index offers enhanced precision in calculations and can easily be integrated into assessments of land-use intensity in grasslands. Further, it could serve as a basis for providing subsidies to farmers, who adopt low-impact mowing practices.