International recognition and metrological traceability

In order for our calibrations and measurements to be internationally recognised, various requirements must be met. These include, in particular, metrological traceability to the International System of Units (SI) and a recognised quality management system.

International recognition

As Switzerland’s national metrology institute, METAS has the task of “providing internationally recognised units of measurement with the required level of accuracy” in accordance with the Federal Act on the Federal Institute of Metrology (EIMG). This recognition is based on our participation in the CIPM Mutual Recognition Arrangement (CIPM MRA), an agreement that enables the worldwide mutual recognition of calibration and measurement certificates. All internationally recognised services, so-called “Calibration and Measurement Capabilities” (CMC), can be viewed publicly in the “Key Comparison Database” (KCDB) of the International Bureau of Weights and Measures (BIPM).

Behind every CMC entry there is a time-consuming verification process. Three prerequisites must be met for this:

• A quality management system according to ISO 17025 for calibrations and according to ISO 17034 for certified reference materials. At METAS, these standards are an important part of the Integrated Management System (IMS).
• A technical certification of competence, typically through participation in an international measurement comparison, the results of which are also published in the KCDB.
• Metrological traceability to an internationally recognised realisation of SI units.

The reciprocal Recognition Agreement between BIPM and ILAC (International Laboratory Accreditation Cooperation) also ensures that the metrological traceability and international equivalence of calibrations from the CIPM MRA are seamlessly incorporated into the global accreditation system and recognised there. Since 2026, the former role of ILAC has been fulfilled by Global Accreditation Cooperation Incorporated (Global ACI) . Accordingly, recognition is taken over by all accreditation bodies in Europe, including:

• Swiss Accreditation Service SAS (Switzerland)
• French Accreditation Committee COFRAC (France)
• German Accreditation Body DAkkS (Germany)
• Spanish National Accreditation Body ENAC (Spain)
• Italian Accreditation Body (Italy)

FAQ

• What is metrological traceability?

  According to the International Dictionary of Metrology (International vocabulary of metrology, VIM), metrological traceability is a “property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty”. METAS often implements the internationally recognised realisation of the SI unit itself – for example with the Kibble balance for the kilogram or the caesium fountain for the second. In other areas, repatriation is carried out via the national metrology institutes of other countries. METAS has designated national institutes for special measured variables.

  Closely linked to metrological traceability is the concept of measurement uncertainty. The measurement uncertainty indicates the range of values in which a measurement result is plausible based on the available information – because every measurement is subject to unavoidable influences over the determined value. If the same measured variable is determined with traceable measurements, the results must match within the combined measurement uncertainty.

• Why is metrological traceability important?

  Metrological traceability is the basis for the comparability of measurement results and thus also for the international recognition of the conformity of devices with specific specifications. Proof of metrological traceability therefore plays a fundamental role in world trade (see WTO Agreement on Technical Barriers to Trade, TBT Agreement, Article 6 Recognition of Conformity by Central Government Bodies). However, metrological traceability is also essential for scientific studies in research and development. In this way, traceable measurement results enable scientific exchange and long-term comparability of research results.

More information

• Federal Act of 17 June 2011 on Metrology (MetrA, SR 941.20)
• International Dictionary of Metrology
• WTO Agreement on Technical Barriers to Trade (TBT Agreement)

• Basics of international recognition

  • CIPM Mutual Recognition Arrangement (CIPM MRA)
  • Calibration and Measurement Capabilities (CMCs)
  • Key Comparison Database (KCDB)
  • Recognition agreement between BIPM and ILAC
  • Global ACI

• Proof of the competence of METAS

  • Overview table of the management systems of national metrology institutes and designated institutes (EURAMET TC-Q)

  • METAS self-declaration on quality management

    PDF306.95 kB18 August 2026

• Metrological traceability requirements

  • Ensuring the traceability of measuring results (SAS document 702)

  • ILAC Policy on Metrological Traceability of Measurement Results (ILACP10:07/2020)

    PDF338.61 kB31 July 2026