Definitions of calibration interval come in many terms, these terms are calibration frequency, calibration period, or simply calibration due date. And to define it more, calibration interval is the number of days between scheduled calibrations.

It will answer the question,” How often should we calibrate our instruments?” Or, “How long before we calibrate our instruments again?”

Having a calibration interval is a must. Saying this, laboratories are not allowed to give a calibration frequency. The calibration interval as per ISO 17025 standard, under clause 7.8.4.3, states that  “A calibration certificate or calibration label shall not contain any recommendation on the calibration interval, except where this has been agreed with the customer.”

One of the reasons is that once the instrument is out of the lab, the lab has no control over it, therefore the calibration interval is not guaranteed. 

The user should determine what are Calibration Intervals needed for his instruments. This will now become part of the In-house Calibration program that should be properly documented.

Any instruments that will not fall under the calibration Interval analysis may fall under the ‘calibration-not-required’ status. Check my other post in this link >> calibration-not-required implementation