This study is motivated by the premise that online consumers can make a purchase at any time of day if they have even a tiny time slot along with Internet access. To identify the increased shopping time flexibility, we first characterize the patterns of online purchase timing in comparison to those in the offline market. The results show (1) the breakdown of purchase timing regularity and (2) the change of weekly spike purchase occurrence. Second, we build online inter-purchase time model and estimate it with the data collected from one of the premier online vendors in Korea. We verify new theories in online consumers’ purchase timing, particularly, about (1) how online consumers’ hazard rates change, (2) how online consumers respond to price promotions, and (3) what factors affect online consumers’ purchasing timing decision. Both marketing researchers and practitioners can gain significant new insight to understanding the nature of online commerce on the time space.