This study aimed to analyse the comparison between the Implementation Budget Plan or Rencana Anggaran Pelaksanaan (RAP) and the Cost Budget Plan or Rencana Anggaran Biaya (RAB) on the work of brick walls and floor tiles in the construction of the Special Official House of the Main Official of the Tabanan Police. The background of this study is based on the importance of controlling construction project costs so that the implementation of work is in accordance with the plan and achieves budget efficiency. The research method used was a quantitative descriptive method with data collection through field observations, interviews, and documentation in the form of RAB, shop drawings, and as-built drawings. The analysis was carried out by calculating the actual work volume, material requirements, and comparing the RAP costs to the RAB. The results of the study showed that the comparison of the RAP costs to the RAB on the installation of brick walls showed a difference, where the costs calculated in the RAP of Rp 83,133,400 tended to better reflect the actual conditions in the field compared to the RAB of Rp 85,286,651 with a difference of Rp 2.153.251 and a percentage of 97.48%. In the installation of floor tiles, there was also a significant deviation, where the cost calculated in the RAP of Rp. 107,209,600 tended to be greater than the RAB value of Rp. 79,108,732 with a difference of -Rp.28.100.868 and a percentage of -1112%. This difference has an impact on cost discrepancies, so that the RAB does not fully reflect the real cost needs in the field. Thus, a comparative analysis of the RAP and RAB is important as a basis for evaluating project costs so that work implementation is more effective, efficient, and according to the planned quality.