When a Gage is past the Calibration Due Date


Does anyone know if a gage goes past the due date if you must immediately mark it as lost or can you give it a grace period?


Trusted Information Resource
I don't know if this is an 'official' answer but our own internal procedure allows us to extend a gage calibration by 3 months if it is in use (and the history of the gage calibration is good) or we can extend calibration by 1 year if the gage has not been used since the last calibration.

I think the answer would be: depends on what your procedures say.


I guess the bigger question is, Why did this happen? What in your system failed to get that gage calibrated on time, and why? If the instrument is unaccounted for, then, yes, it should be marked as lost. If it merely "slipped through the cracks," then marking it as lost is simply being dishonest with yourselves, your customers, and your auditors.

It's important to find the cause of this error and correct it.


Moved On
Does anyone know if a gage goes past the due date if you must immediately mark it as lost or can you give it a grace period?

An effective management system control for such equipment will have a method of granting extensions, based on DATA from previous calibrations etc.


Trusted Information Resource
Does anyone know if a gage goes past the due date if you must immediately mark it as lost or can you give it a grace period?
clearly, it depends. Yes, it depends on previous history, and also current status of the equipment.
(of course on SOP, but more so on the understanding-the-criteria or risk....
1) nature/critical of the gage (i.e., instruments vs, equipments viz., balances, weights, pH meters, thermometers, etc)
2) frequency of calibration (obviously, the ones which are recommended for daily calibration cannot be extended!!!)
3) nature of calibration standards (if reference lots have changed, especially true for chemical labs)

Tiny Timm

First get the gauge calibrated immediately when found and identified as being late in calibration. If you cannot get it calibrated then verify it against a known calibrated gauge that is similar. Example - gauge blocks are late for calibration but you have a caliper that is calibrated against another set of gauge blocks. Use that caliper to verify if the late calibration blocks are within the acceptable value to continue to use.
Second only if the gauge is lost should you mark it lost. Use a term like past due or not for calibrated use or calibrate before use.
Third, like others have stated, your procedures should have a grace period or a built in +/- around the due date.


Quite Involved in Discussions
I agree that your internal processes should dictate what to do about late calibrations. And yes, what did happen that they became late?

A robust recall system gives plenty of advance warning, via email and/or distributed hard-copy notices to equipment owners and supervisors, or other responsible persons, that equipment is coming due.
The only reason a grace period is needed is failure of the above; a grace period is an excuse for non-compliance.
Upper management buy-in is necessary to enforce metrology system policies. They are the hammer.

Extensions should be granted before, not after, they go overdue in accordance with your policy (30 days is the max at my location), which should include historical evidence that the equipment will have a high probability to stay in tolerance.

Extending equipment by longer is effectively changing the recall interval. Since probabilities are part of establishing the interval, including end-of-period reliability at either the model or test point level, you diminish their robustness when the established recall period is extended by too long (tail wags dog).

I would liken checking a reference artifact (gage block) with a caliper to make a serviceability decision to using a hand-held DMM to determine if a Multifunction Electrical Calibrator is OK. Not a desirable method.
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