Calibration knowledge centre
What is calibration? Meaning, process and importance
Calibration compares an instrument indication with a reference standard under defined conditions to establish measurement error and uncertainty. The result helps users decide whether the instrument is suitable for its intended application and acceptance criteria.
Calibration is not the same as adjustment
Calibration measures and reports results. Adjustment changes an instrument to reduce error. When adjustment is needed, as-found and as-left results should be distinguished so prior measurement impact can be reviewed.
A typical instrument calibration process
1. Review requirements
Confirm instrument type, operating range, points, resolution, criteria and service location.
2. Inspect and identify
Record identity, accessories, condition and damage before work.
3. Compare with references
Apply a suitable method under controlled conditions and record reference and instrument results.
4. Evaluate results
Calculate error, uncertainty and information needed for fitness decisions.
5. Issue and review the certificate
Report results, conditions, method, references and traceability information.
Why instrument calibration matters
- ✓Supports confidence in process measurements
- ✓Reduces incorrect acceptance decisions
- ✓Supports ISO, GMP and other quality systems
- ✓Provides evidence for stability monitoring
- ✓Demonstrates metrological traceability where supported
What to review on a calibration certificate
Check instrument identity, date and location, environmental conditions, method, point results, uncertainty, units, reference standards and traceability statements. Define acceptance criteria and decision rules before work if conformity statements are required.
How often should instruments be calibrated?
No single interval suits every instrument. Base the interval on risk, usage, environment, drift history, product impact and regulatory or customer requirements. Six or twelve months is only a starting point for data-based review.
FAQ
What is calibration in simple terms?
It compares an instrument result with a reference standard to establish error and uncertainty under defined conditions.
Does calibration mean an instrument passes?
Not automatically. Calibration provides measurement results; conformity needs agreed acceptance criteria and a decision rule.
Why is ISO/IEC 17025 relevant?
It addresses laboratory competence, but customers should also confirm that the accredited scope covers the required instrument and range.