People constantly compare their appearance and well-being to that of other individuals. However, there is a lack of a measure of social comparisons of well-being, and existing appearance-related social comparison scales assess social comparison tendency using predefined social situations. This limits our understanding of the role of social comparison in self-evaluation and well-being. Therefore, we developed the Scale for Social Comparison of Appearance (SSC-A) and the Scale for Social Comparison of Well-being (SSC-W) that assess downward and upward social comparisons with regards to a) frequency, b) perceived discrepancy, and c) affective impact during the last three weeks. In one longitudinal and three cross-sectional studies with sample sizes ranging from 500 to 1,119 participants, we administered the SSC-A or the SSC-W alongside measures of appearance social comparisons, body satisfaction, self-concept, social rank, psychological well-being, envy, rumination, depression and anxiety. Confirmatory factor analyses supported the expected two-factor solution representing upward and downward social comparisons for both scales. Their validity was supported by significant associations with the measured constructs. Overall, upward comparisons displayed higher associations with most measured constructs than downward comparisons. The SSC-A and SSC-W offer parsimonious, reliable and valid measures of social comparisons of appearance and well-being.