For the quality implementation of bilateral comparasion of pressure measurements in the range from 0 to 600 bar it is necessary to know all the concepts that connect with the term metrology. In the introduction part of this paper, with a brief history of measurement, the meaning of International System of Units and the Functioning of Metrology Infrastructure are explained. After the general introduction to metrology, a detailed explanation of the concept of pressure and of the essential concepts for inter-laboratory comparisons are given, such as calibration, traceability and metric uncertainty. The pressure measurement is carried out by a device called the pressure balance according to precisely defined and prescribed rules. The basic conditions for calibration and calibration methods by EUROMET are also mandatory, so that the measurement results are internationally recognized. Furthermore, the standards and instructions required for inter-laboratory comparisons and result processing are listed and the comparison protocol itself for a pressure of 0 to 600 bar. The measurement was performed in the calibrated BMB Brcković laboratory and the LPM-FSB laboratory. The electric pressure transmitter P-30, WIKA was used for calibration. After the measurement was carried out, the analysis of the comparison results was carried out, the En value was specified, which was also the aim of this paper.