Practical guide to understanding a calibration certificate
1. Certificate header
Contains general information:
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Certificate number: Identifies the traceability document.
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Client and filing: Relates the service to the requesting company.
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Calibrated instrument: Includes type, brand, measurement range and serial number.
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Reception and calibration dates: Important for validity control.
2. Master team data
They show metrological traceability:
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Standard instrument: Reference equipment used.
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Standard certificate: Document that demonstrates its calibration.
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Pattern uncertainty and CMC: They guarantee the reliability of the measurements.
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Method used.
3. Environmental conditions
Temperature, humidity and atmospheric pressure are recorded as they affect accuracy.
4. Readings taken
The readings taken at each calibration point are presented.
5. Calibration results
The table presents for each point:
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Indicated pressure (Pind)
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Standard pressure (PStandard)
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Deviation (Δp)
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Expanded uncertainty (U)
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Declaration of conformity (Compliant / Non-compliant)
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Graph with the calibration curve
👉 “Compliant” means that the instrument meets the established tolerance.
6. Acceptance criteria, decision rule and declaration of conformity
They define whether the instrument meets the manufacturer’s specifications.
7. Measurement uncertainty
Represents the confidence level of the result (≈95% with k=2).
8. Traceability declaration
Confirms that measurements are traceable to the International System of Units (SI) through standards calibrated in WIKA–Germany (DKD, DAkkS, ILAC).
9. Signature and authorization
The certificate must be electronically signed or printed by the technical staff and the director of the accredited laboratory.
Conclusion: Reading a calibration certificate correctly allows:
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Check the compliance of your instrument.
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Ensure traceability of measurements.
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Determine when it should be recalibrated.