The aim of this study was to investigate the effect of different loading symbols and loading durations on online video viewers’ perception of waiting time. Sixty young adults participated in this study and their subjective ratings on waiting time perception for forty-eight different loading symbols (3 durations × 4 progress functions × 2 shapes × 2 embellishments) were obtained through a 7-point Likert scale. Each participant chose two best loading symbols in terms of waiting time perception at the end of the experiment. Results showed that duration and the progress function practically affect the viewers’ waiting time perception, and shape and embellishment don’t. Loading symbols of power and inverse power progress functions are perceived shorter than those of the repetitive and linear progress functions. It is recommended to show loading progress and use manipulated progress functions, and design factors such as shape and embellishment are considered to be less important for designing a better loading symbol. The circle shaped symbol with repetitive progress function, which is most commonly used in online video websites, showed significantly worse performance than others. The findings of this study may serve as a useful input for video service providers and symbol designers in creating shortly perceived loading symbols.