<![CDATA[The calculation of state financial losses constitutes a fundamental element in proving corruption offences, particularly those involving regional public finances, as it establishes the existence of financial losses resulting from unlawful conduct. Although the Audit Board of the Republic of Indonesia (BPK) possesses constitutional authority under Article 23E of the 1945 Constitution and relevant legislation, the implementation of this function continues to encounter significant institutional and procedural challenges. This article aims to examine the factors hindering the optimization of BPK's constitutional function in calculating state financial losses during the investigation of corruption cases involving regional public finances and to formulate an institutional strengthening model. This research employs a normative legal research method using statutory, conceptual, case, and comparative approaches. Legal materials were analyzed qualitatively through legal interpretation and doctrinal analysis. The findings indicate that the principal obstacles arise not from the absence of legal authority but from inconsistent interpretations of BPK's functions, fragmented technical regulations, inadequate inter-agency coordination, dependence on investigators' case construction and evidence, limited institutional capacity, evidentiary complexity, and insufficient methodological standardization and quality assurance. The proposed model strengthens BPK's constitutional function by enhancing legal certainty, institutional effectiveness, and the reliability of evidence in corruption investigations.]]>
