A Japanese version of the short form of the expanded Posttraumatic Growth Inventory (PTGI-X-SF-J) was developed in this study, as the extended version captures broader, more diverse personal growth perspectives, such as existential spiritual growth. We collected cross-sectional data from 408 (first sample) and 284 (second sample) Japanese university students using the expanded version of the Posttraumatic Growth Inventory (PTGI-X-J). Exploratory factor analysis (EFA) was performed with the first sample and confirmatory factor analysis (CFA) with the second; reliability and validity were examined. The short-form version resulting from the EFA and CFA comprised 10 items and five factors. Cronbach’s alpha for the PTGI-X-SF-J total and subscale scores ranged from 0.671 to 0.875. The intraclass correlation coefficient for the total and subscale scores between the PTGI-X-J and PTGI-X-SF-J ranged from 0.699 to 0.821. Regarding external validity, no significant correlation was found between posttraumatic growth and posttraumatic stress disorder checklists. Due to its brevity, the PTGI-X-SF-J can help assess diverse spiritual and existential personal growth experiences among clients, patients, and trauma survivors while reducing physical and psychological burdens.