FLEXcel is an Excel-based tool, developed within the FLEXcheck project, to support the quick estimation of industrial flexibility potentials. By combining a structured questionnaire with simplified calculation routines, FLEXcel enables companies to assess their technical flexibility using only limited process and energy data. The tool is designed as a low-threshold entry point for identifying shiftable loads and operational adjustments, providing decision support on whether more detailed analyses or investments in flexibility are warranted. With a clear focus on the Austrian market, FLEXcel is provided in German to ensure practical usability for local companies and stakeholders.