Judging one's creativity compared to others is a complex task, which raises the question of what information people rely on when making these judgements. We studied a sample of 400 people who assessed their creativity on a percentile-type scale (0-100) relative to others (i.e., global creative self-concept; CSC), justified their judgements openly, and completed several other measures of CSC, real-life creativity, Big-5 personality as well as traits that are known to influence self-assessments (e.g., self-esteem, narcissism, and tendency for social comparison). The global CSC self-assessment was highly related to other domain-general CSC measures but still was associated more strongly with CSC in some domains (e.g., visual arts) compared to others (e.g., scientific creativity). Justifications of CSC self-assessments were analyzed in the context of Bandura's four sources of information, which revealed that mastery experience was the most salient source for these judgements. In fact, higher CSC was related to recalling more mastery experiences and mentioning fewer (often negative) vicarious experiences. Results further showed that CSC was correlated more to creative activities than to creative achievements, and was related to higher openness, self-esteem, self-concept clarity, narcissism and lower tendency for social comparisons. In sum, findings offer insights into how personal experiences, besides broader personality traits, contribute to viewing oneself as more versus less creative.