Description: In the article the question of an estimation of the least reached uncertainty of measurements of the calibration laboratory accredited on conformity to requirements of the standard ISO/IEC 17025. Since the uncertainty of measurements is a quantitative measure of measurement accuracy, the evaluation of measurement accuracy is one of the tasks of ensuring their unity. One of the essential criteria characterizing the scope of accreditation of a calibration laboratory accredited by the National Agency for Accreditation of Ukraine for compliance with the requirements of ISO / IEC 17025 is the smallest attainable measurement uncertainty. The analysis of the “scope of accreditation” of calibration laboratories shows that due to the lack of standardized calibration techniques for measuring instruments, the laboratories have to develop the techniques themselves based on their experience and knowledge. This state of affairs in assessing the quality of measurements does not contribute to ensuring their unity. The procedure for estimating the smallest achievable measurement uncertainty in calibrating a digital caliper was considered, sources of uncertainty were identified and evaluated, and an uncertainty budget was drawn up. The quality of the assessment of calibration and measurement capabilities depends on common sense, critical thinking and professional integrity of the personnel of the calibration laboratory involved in obtaining it. The development of a unified regulatory and methodological document to clarify the assessment of measurement uncertainty in the calibration of measuring equipment means the key to ensuring uniformity of measurements in Ukraine.
Keywords: calibration laboratory, accreditation, calibration of measuring equipment, measurement uncertainty, calibration and measurement capability