In this study, a subjective well-being scale was developed, and its reliability and validity evaluated. The Subjective Well-Being Scale (SWBS) had twelve items which covered four domains. It was administered to 1005 adults and 520 college students. Results indicated that for the students, college life satisfaction and self-esteem had positive correlations with SWBS score. For the adults, marital satisfaction, workplace satisfaction, and household income satisfaction had positive correlations with the score. These findings showed considerable constructive validity for SWBS. In addition, internal consistency was sufficiently high, indicating the measure's high reliability. SWBS may be a simple but reliable and valid measure, and it is useful for examining subjective well-being of both adults and college students.