People often predict the workload in advance before they start a given task. Based on the mere association effect and the metaphor relationship between the workload and the physical length, we suggested that people predict their workload based on the physical length appearance. The substitution of the physical length for the anticipated workload can be evoked due to the abstract feature of the workload, and thus it is represented either by the mere association with the certain trait people used to hold, or by the metaphoric inference using concrete concept or experience they are familiar with. Either, it can be naturally predicted that physical appearance can be used as inference for the workload. Study 1 found out that the participants given the physically shorter appearance of contents (double-sided print option) predicted less workload for the task, relative to the participants presented with the physically longer appearance (one-sided print option) of the contents, although the actual amount of the contents was same. Study 2 confirmed that this metaphor could be applied into the assembly task, beyond the reading task, as well. The participants given the manual script which was printed in a double-sided option anticipated less workload to assemble the drawer, relative to participants presented with the manual script printed in a one-sided option, although both groups were given the same amount of the contents. Two studies supported our hypothesis that the physical appearance of the contents matters when people predict the workload of the task.