Currently, Indonesia still uses tax revenue as the main source of state revenue. However, the problem occurred when for several years it turned out that tax revenues did not meet the target. The percentage of realized tax revenues compared to the tax revenue target from year to year indicates that the ratio of tax revenues did not reach the target. One of the factors causing the non-achievement of tax revenue is related to the number of employees of the Directorate General of Taxes who are still not ideal with their workload. This study aims to determine how to calculate the efficiency level of capacity costs by using the theory of Time Driven Activity Based Costing (TDABC) in the utilization of currently available resources at the Tax Service Office, Kantor Pelayanan Pajak (KPP) Pratama Binjai. The population of this research is all the executor of the Service Section and Account Representative who are in KPP Pratama Binjai. The researcher uses descriptive (qualitative) data analysis method which only aims to explain the observed facts/practices based on certain theories. This study uses primary and secondary data from KPP Pratama Binjai. The results show that through the TDABC theory, the level of capacity cost efficiency at KPP Pratama Binjai is included in the less efficient category, which means that there is still a lot of unused capacity that should be maximized from available capacity and used capacity.
Keywords: Time Driven Activity Based Costing (TDABC), Efficiency, Available Capacity, Used Capacity, Unused Capacity.