The aim of this study was to develop a novel assessment tool utilizing Schlossberg's 4S model (Situation, Self, Support, and Strategies), with a specific focus on assessing the career transition of high school senior students to university. The study group consisted of high school students from five different high schools. The pilot and trial administration involved a total of 85 individuals; the exploratory factor analysis included an additional 1099 participants, and the confirmatory factor analysis collected data from 273 individuals. The reliability and validity approaches employed, such as expert opinions, exploratory and confirmatory factor analysis, test-retest administration, item discrimination, internal consistency findings, and model fit indices, all demonstrated satisfactory values, indicating that the scale is valid and reliable. The factor analysis research reveals that the scale comprises three distinct dimensions: situation, self, and support, with a total of 23 items. However, the dimension of strategies is needed to demonstrate an adequate fit for this research's specific demographics. This assessment instrument is anticipated to substantially impact the field of education by enhancing the ability of school counselors and teachers to intervene more effectively in students' career planning efforts.