What should a calibration certificate contain?

A calibration certificate is a technical record. Its purpose is to let someone who was not present reproduce what was done, judge whether the result is fit for their use, and trace it back to references. ISO/IEC 17025 lists the information an accredited certificate must contain; the items below are the ones that most often matter in practice.

Identification

• Unique certificate number and page numbering.
• Laboratory identity and, for accredited work, the accreditation body and scope reference.
• Customer identity.
• Unambiguous identification of the item calibrated (model, serial number, identifier).
• Date(s) of calibration and date of issue.

Method and conditions

• The method or procedure used, and any deviations from it.
• Environmental conditions where they affect the result.
• The reference standards used and evidence of their traceability.

Results

• Measured values with units, at each calibration point.
• Measurement uncertainty with the coverage factor, presented alongside the results.
• As-found and as-left data where adjustment or repair was performed.
• Any statement of conformity together with the decision rule applied.
• Authorisation: the name and role of the person approving the certificate.

Digital certificates

Machine-readable digital calibration certificates carry the same content in structured form, allowing uncertainty information — including Monte Carlo results — to be stored and re-used without transcription. ValiTrac's approved knowledge base includes a national metrology institute case study on generating and using such certificates.