Researchers work hard to create and disseminate cutting-edge scholarship, and tracing the impact of and interaction with this work is important. The Metrics Toolkit assists researchers with this task by "provid[ing] evidence-based information about research metrics across disciplines, including how each metric is calculated, where you can find it, and how each should (and should not) be applied." Included metrics range from social media sites (e.g. Twitter mentions) to scholarly platforms (e.g. Mendeley Readers), to software databases (e.g. GitHub). For each metric users will find an outline of key information, making it easier to find the best tools for their specific needs. A chart highlighting what each field means is found on the About the Toolkit tab (under Metric Description Schema). Readers new to this type of evaluation may be wondering why metrics matter. Check out the Use Cases tab for examples of how this data has enhanced several projects. The Resources tab also houses general information on metrics and research evaluation. The Metrics Toolkit is populated by a global editorial board and supported by Altmetric, Indiana University-Purdue University Indianapolis, and FORCE11.