Factors to consider
- Instrument type, stability, and manufacturer guidance
- Frequency and severity of use
- Measurement risk and the consequence of an inaccurate result
- Historical drift, failures, repairs, and out-of-tolerance findings
- Customer, regulatory, or internal procedure requirements
- Storage, transport, and environmental conditions
Does NIST recommend an annual calibration interval?
NIST does not prescribe a single recalibration interval for all instruments. Its guidance points to the application's accuracy needs, applicable requirements, instrument stability, and environment. The interval should be supported by evidence about the instrument and how it is used; an annual schedule is not a universal rule.
Read NIST's calibration interval guidance →Keep an interval decision record
Use the following fields in your controlled procedure or decision log. GagePilot stores the chosen interval and due date; the supporting assessment and approval should remain retrievable from your quality records.
| Field | What to record |
|---|---|
| Scope | The instrument ID or defined group, its measurement task, and the relevant operating conditions. |
| Current basis | The existing interval and its source, such as manufacturer guidance or a prior approved assessment. |
| Evidence reviewed | Calibration history, failures, repairs, checks, and changes in usage or environment. |
| Decision | Retain or change the interval, with a reason and any conditions or follow-up checks. |
| Approval and effective date | Who authorized the decision, when it takes effect, and the resulting next due date. |
| Next review | The date or event that will trigger another assessment. |
Example: the same instrument type can need a different review
Two micrometers may have the same model number but different operating histories. One stays in a controlled inspection room; the other travels between production stations and has recently been repaired. Start the review with those differences and the measurement task, rather than copying the same interval solely because the models match.
The review may retain the current interval or approve a change. This example does not prescribe a number of months: the authorized decision must follow your procedure and evidence. A repair, failure, or change in use can trigger a review before the next calendar checkpoint.
Document the decision
- Define the initial intervalUse your approved procedure, manufacturer guidance, or a documented risk-based method.
- Record the next due dateThe date should be traceable to the last completed calibration and the chosen interval.
- Review the historyLook for repeated failures, stable performance, or changes in use that justify a review.
- Update consistentlyIf an interval changes, document who approved it and update the register so future reminders reflect the decision.
Avoid a calendar-only approach
A fixed annual interval may be appropriate for some instruments and inappropriate for others. Use the date as a control point, then review the evidence and procedure that support the interval.