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We investigated whether visual complexity of novel abstract patterns affects perceived duration. Previous research has reported that complex visual stimuli led to an underestimation of durations. However, to clarify the nature of the time estimation process, it is necessary to establish which component of image complexity, spatial or semantic, plays the critical role. Here we tested the impact of specific spatial properties. We used unfamiliar and abstract patterns made using black-and-white checkerboards in which the difference between stimuli was exclusively in configuration. Visual complexity was quantified by the GIF index based on a compression algorithm, which scanned the pattern in both horizontal and vertical directions. This metric correlated positively with subjective complexity (Experiment 1A). In the second study, we increased variability in the stimuli by changing the number of items across patterns while keeping overall size constant. A high positive correlation was found between objective and subjective complexity (r= 0.95)(Experiment 2A). In Experiments 1B and 2B, observers estimated pattern durations in seconds using a continuous scale. A multilevel linear analysis found that perceived duration was not predicted by visual complexity for either of the two sets of stimuli. These results provide new constraints to theories of time perception, hypothesizing that complexity leads to an underestimation of duration when it reduces attention to time.