<p>This article thoroughly studies the process of calibrating sound level <br /> meters based on the requirements of the international standard IEC 61672-<br /> 3:2013 and its significance. Accurate measurement of sound pressure level <br /> plays an important role in environmental monitoring, industrial noise control, <br /> healthcare, and occupational safety. The main goal of the research is to <br /> analyze the calibration process in accordance with the standard requirements <br /> for acoustic parameters of sound pressure level measuring instruments. The <br /> article details the theoretical foundations of the calibration of sound level <br /> meters, measurement methods, and calculation formulas. We also present the <br /> components that comprise the measurement uncertainty, which include the <br /> acoustic multifunctional calibrator, sound level meter, and its microphone. <br /> We looked at the measurement uncertainty using a visual analysis method and <br /> figured out the percentage of each uncertainty component compared to the total <br /> sum. The study used the “MK 265” microphone model from “Ассистент” with <br /> the factory number 450924, and based on the results, it looked at which parts <br /> of the uncertainty had the biggest and smallest impact on the measurement <br /> uncertainty, and suggestions were made to reduce uncertainty and improve <br /> measurement methods.</p>