Time seems to speed up as one ages, and it affects how people find meaning in life and plan their future. What creates this perception? We examine the role of “chunking” – mentally bundling individual moments of experience under broad categories. With age, people group experiences into progressively bigger chunks (e.g., work, family). Consequently, fewer things seem to have occurred in a given period, so it seems to have passed faster in retrospect. Supporting this account, three studies (overall N = 324) show that people led to chunk (vs. not chunk) their past year perceived it as passing faster. The effect of chunking emerged reliably across converging operations and specifically accelerated the chunked period, not other periods. Furthermore, chunking increased the appeal of nostalgia, suggesting that processes that accelerate time instigate a compensatory urge to reflect on momentous occasions of one’s life. Implications for the “self across time” are discussed.