Generally, Calibration is non-destructive process, unlike some testing where sample may or may not be subjected to physical change. Calibration is a process by which measurement relationship is established with the reference standard / master, which has un-broken chain of measurement called measurement traceability. The calibration process does not end with above statement, during the process factors like environmental condition, measurement uncertainty of reference master, uncertainty due to variations in observed values, accuracy of device is some of the factors which are taken into account while calibration.

Various standards are followed to calibrate a given instrument; these standards are published by various organisations like ISO. This standard calibration practice is followed all over the world by reputed organisations and accredited calibration laboratory