Recent research on time-based expectancy has shown that humans base their expectancies for responses on representations of temporal relations (e.g., shorter vs. longer duration), rather than on representations of absolute durations (e.g., 500 vs. 1000 ms). In the present study, we investigated whether this holds also true for time-based expectancy of tasks instead of responses. Using a combination of the time-event correlation paradigm and the standard task-switching paradigm, participants learned to associate two different time intervals with two different tasks in a learning phase. In a test phase, the two intervals were either globally prolonged (Experiment 1), or shortened (Experiment 2), and they were no longer predictive for the upcoming task. In both experiments, performance in the test phase was better when expectancy had been defined in relative terms and worse when expectancy had been defined in absolute terms. We conclude that time-based task expectancy employs a relative, rather than an absolute, representation of time. Humans seem to be able to flexibly transfer their time-based task expectancies between different global timing regimes. This finding is of importance not only for our basic understanding of cognitive mechanisms underlying time-based task expectancy. For human-machine applications, these results mean that adaptation to predictive delay structures in interfaces survives globally speeding up or slowing down of delays due to different transmission rates.