Calibration levels guidance

There are typically four levels of calibration compliance offered by calibration laboratories. Compliance level is determined by the calibration certificate details only, not supporting claims from other locations.

ISO 17025 audited (traceable) calibration 

ILAC-NATA Accreditation Logo This is the highest level of calibration certificate.

The calibration report includes full test data and uncertainty. The calibration certificate must show the laboratory accreditation body logo, the laboratory accreditation number. and may show the ILAC logo. The accreditation body will have a web site where the accreditation scope of the laboratory is available to the public. The calibration certificate is internationally recognised.

The calibrated instrument is traceable, and can be used by anyone to calibrate other equipment in compliance with ISO 9001.

When this calibrated instrument is used by another accredited laboratory, the calibrated instrument can be used to traceably calibrate other equipment. The laboratory is externally audited by an accreditation organisation that operates within ISO/IEC 17011 and is an ILAC signatory.

Some National Measurement Institutes do not reference ISO 17025, but are at an equivalent level on the basis of peer review or other.

The calibration equipment is traceable. The calibrated instrument is traceable.

Why ISO17025? further reading

ISO 17025 unaudited calibration 

This type of calibration certificate can be more useful than the ISO9001 level, if good test data is attached, along with test condition & uncertainty details. Successive test reports can be used to determine a rate of drift of the item, then calibration periods may be extended. The calibration laboratory claims ISO17025 compliance, but it is not externally audited / accredited.

The calibration certificate does not include an external laboratory accreditation body logo (such as NATA, NIST, METAS etc. Possibly additionally ILAC), and it references ISO17025.

The calibration equipment is traceable. The calibrated instrument is not traceable.

ISO 9001 compliant calibration

The certificate does not have an external laboratory accreditation body logo, or reference to ISO 17025, it may reference ISO9001. It should state that the equipment used for calibration is traceable. 

These certificates are commonly pass / fail or QA certificates, with or without test data.

The calibration equipment is traceable. The calibrated instrument is not traceable.

Non-compliant calibration

This type of calibration certificate is of little formal value, since it does not meet any compliance requirements, but may be sufficient for casual users.

The certificate does not refer to an external laboratory accreditation body or ISO17025, it may reference ISO9001. These are commonly just pass / fail or QA certificates, with no test data.

The calibration equipment is not traceable. The calibrated instrument is not traceable.