Certain embodiments of the invention may include systems, methods, and apparatus for determining online stress and life of a heat recovery steam generator. According to an example embodiment of the invention, a method for assessing components related to a heat recovery steam generator (HRSG) is provided. The method includes receiving HRSG design parameters (128); monitoring thermal stress data from one or more temperature sensors in communication with one or more HRSG components (122); and determining cycle-related life consumption data associated with the one or more HRSG components (122) based at least in part on the HRSG design parameters (128) and the monitored thermal stress data.