At present, economic interests of product manufacturers and consumers are the main criteria for choosing measuring instruments. Loss reduction from internal and external faultscan be ensured through the detection of measurement discrepancies, as well as by reducing the defects of the 1st and 2nd kind, which are manifested due to the presence of measurement errors. The authors have worked out a methodology for determining the economic efficiency from the use of a new measuring instrument as compared with the conventional (basic) one, which includes all the parameters characterizing the losses due toinaccurate measurements, monitoring costs and the cost of measuring instruments. Choosing measurement instruments for controlling shaft diameters of a unified reducer produced by Mosselmash has been offered as an example. The ИЧ-10 indicator that used to be employed before in the C-III rack when adjusting by the end gauge rods of Grade 3 (with an error of 8 μm) is proposed to be replaced with the bracket CР-25 in the rack when adjusting by the end measures of Grade 2 (with an error of 3.5 μm). As a result of the economic effictassessment, it has been revealed that the number of incorrectly accepted and rejected parts has been reduced in almost 3 times. The economic effect has amounted to 92,704.89 rubleswith the control program of 3000 pcs. a year. The study has confirmed the expediency of using a more accurate means of measurement, which allows increasing the efficiency and result rating of input and output inspection at a technical service enterprise.