I In every machining process, priority is given to the perfect final result, and the perfect result cannot be separated from the various measuring tools that support the machining process, one of which is the parallel block. This parallel block is used as a tool in the machining process, where in its use this parallel block is clamped together with the workpiece. The purpose of this study was to determine the geometric characteristics of parallelism, perpendicularity and straightness of parallel blocks whether they are in accordance with the standards of DIN 6346 and DIN ISO 2768. The research method used is a direct measurement method using a dial indicator and height gauge by means of repeated measurements. repeated so that the minimum and maximum deviations are obtained which will be compared with the standard tolerance of DFN 6346 and DIN ISO 2768. The results of the validation test of the geometric accuracy of parallelism, perpendicularity and straightness of parallel blocks, the deviations are still within the allowable standard tolerance limits. Therefore, the bl •allele is declared valid and feasibleto use.