The function of this algorithm is to optimize load profiles for testing polymer electrolyte membrane (PEM) fuel cells. The load profiles are based on standardized driving cycles in mobile applications. More precisely, the algorithm decreases the length of a load profile while maintaining the same degradation behavior as the original load profile. Like this, a realistic accelerated stress test (AST) for PEM fuel cells used in mobile applications is created. It consists of four sub-algorithms representing the four modes which are mostly responsible for degradation during operation in mobile applications: voltage cycling, idling conditions, humidity cycling and high load operation. The sub-algorithms analyze each point of the load profile taking the operation conditions as e.g. the temperature and pressure into account and evaluate if the point is degradation-accelerating regarding the respective sub-algorithm. If this is the case the point is included in the resulting AST and if not it is eliminated from the cycle. The version uploaded here is version v1.0, which was used for the publication mentioned below. The algorithm and its documentation will be continously improved and updated with more functions in the referred GitHub repository: FuelCellRealASTGenerator A more detailed description of the algorithm's working principle can be found in the corresponding publication (DOI: 10.1016/j.jpowsour.2024.234959). Please cite this publication if you use the algorithm in a publication as follows: Thiele, P.; Gouveia, L.; Ulrich, O.; Yang, Y.; Liu, Y.; Wick, M.; Pischinger, S. Realistic accelerated stress tests for PEM Fuel Cells: Operation Condition Dependent Load Profile Optimization. In: Journal of Power Sources 617:234959 (2024). DOI: 10.1016/j.jpowsour.2024.234959.