Calibration is the process of establishing the relationship between the values indicated by a measuring instrument or system and the corresponding known values provided by a reference standard. It ensures the accuracy and reliability of measurements by comparing them against recognised benchmarks under specified conditions.

Calibration is essential in maintaining measurement traceability and consistency across laboratories, industries and international borders. It applies to a wide range of instruments, including thermometers, pressure gauges, balances, spectrometers and dimensional tools.

Calibration laboratories may seek accreditation to ISO/IEC 17025, which specifies general requirements for the competence of testing and calibration laboratories.