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Measurement terminology
Calibration, verification and adjustment: what is the difference?
About 6 minutesLast reviewed: 2026-08-31
These activities are related but produce different outcomes. Correct terminology helps define the work, criteria and evidence required.
What each activity means
Calibration establishes a relationship with a reference and reports error and uncertainty. Verification confirms that specified requirements are met. Adjustment changes the instrument to reduce error.
- Calibration does not automatically mean pass
- Verification needs a defined requirement
- Adjustment should distinguish as-found and as-left results
Choosing the appropriate activity
Use calibration to understand measurement performance, verification to confirm requirements, and authorized adjustment when error needs to be reduced.
- Specify as-found and as-left needs
- Agree criteria and decision rules in advance
- Review prior impact when results do not conform
FAQ
Must every calibration include adjustment?
No. Adjustment is only appropriate when performance and use indicate that error should be reduced, with as-found evidence retained.
Does verification consider uncertainty?
Conformity decisions should address measurement uncertainty and a suitable decision rule based on risk.