This study proposes an exploratory index of risk to privacy leakage on social media. The purpose of proposing this privacy risk index (PRI) is to understand widely people’s sensitivity toward their personal information explosion in this highly connected network society. We mainly focus on two types of online privacy disclosure with three measures and examine the extent to which online users value and concern the right of privacy: static privacy (personal information including real names, fans page the users join in), and dynamic privacy (location-tagged). Data collected from 305 university students in Taiwan who were recruited to answer the questionnaire. We measured each respondent’s PRI, and the higher score means one’s Facebook behaviors make her or him more vulnerable to online social media privacy leakage, and vice versa. Furthermore, we use PRI to examine the relationship between individuals’ attitude and their behaviors on Facebook. The results show there is no significantly different between the participants’ attitudes and behaviors toward privacy concerns in terms of disclosing their static privacy. However, lower PRI users cared more about dynamic privacy leaking than higher PRI users. In sum, the PRI is a simple but straightforward tool to assess one’s risk of online privacy leakage. As the function settings of the FB platform become more complicated, the related variables of the PRI are also more diverse. We suggest that more online privacy concerns could be melt into PRI to evaluate one’s vulnerability of privacy leaking along with the technical tools developed to collect personal information without full acknowledgment.