How to set and review calibration intervals

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

Document the decision

1. Define the initial intervalUse your approved procedure, manufacturer guidance, or a documented risk-based method.
2. Record the next due dateThe date should be traceable to the last completed calibration and the chosen interval.
3. Review the historyLook for repeated failures, stable performance, or changes in use that justify a review.
4. 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.