Indonesian Muslims’ intention to adopt the global Islamic calendar

The unification of the Global Islamic Calendar (GIC) remains a longstanding aspiration in the Muslim world, however its implementation continues to encounter theological, methodological, and social challenges. Although there are quite a number of normative studies on the global Islamic calendar, empirical studies examining the psychological factors that influence adoption at the national level in a country are still limited. This study investigates the behavioral determinants shaping Indonesian muslims’ intention to adopt the Global Islamic Calendar, employing the theory of planned behaviour as the analytical framework. The study tests the hypotheses that attitudes, subjective norms, and perceived behavioral control significantly influence adoption intention and behavior. Data were collected through an online, non-probability survey of 420 Indonesian muslim respondents through conducted September to October 2025. Structural Equation Modeling was used to examine the relationships among attitudes, subjective norms, and perceived behavioral control on adoption intention and actual behavior. Based on the surveyed sampel, the findings indicate that the acceptance of the GIC is deeply rooted in strong socio-religious dynamics, where religious authorities and community leaders play a pivotal role in shaping public perception. The study recommends that policy strategies for GIC implementation integrate multi-level stakeholder engagement, targeted educational campaigns, and digital dissemination to strengthen attitudinal support and enhance accessibility. Aligning normative pressures with supportive attitudes and accessibility enables the GIC to enhance unity, minimize disputes, and strengthen global Muslim solidarity.