International Organization of Legal Metrology (OIML)

General Detail

General Information

  1. Type: Convention
  2. Date of signature:
  3. Place of signature: Paris, France
  4. Depositary:
  5. Date of entry into force: 28/05/1958


Institutional Participation

Sub category

International Trade Law


What is it about?

The International Organization of Legal Metrology (OIML) is an intergovernmental organization established in 1955 in order to promote the global harmonization of legal metrology procedures. Legal metrology refers to the legislative, administrative and technical procedures established by, or by reference to, public authorities and implemented on their behalf in order to specify and to ensure, in a regulatory or contractual manner, the appropriate quality and credibility of measurements related to official controls, trade, health, safety and the environment. OIML membership includes Members States, countries which participate actively in technical activities, and Corresponding Members, countries which join the OIML as observers. The “Bureau International de Métrologie Légale” (BIML) is the Secretariat and headquarters of the OIML, ensuring both the Organization’s day-to-day administration and the planning of longer-term actions. Since 1955, the OIML has developed a worldwide technical structure that provides its Members with guidelines for the elaboration of national and regional requirements concerning the manufacturing and use of measuring instruments for legal metrology applications. In particular, OIML introduced in 1991 the Certificate System for Measuring Instruments. The system provides the possibility for a manufacturer to obtain an OIML Certificate and a Test Report indicating that a given instrument type (pattern) complies with the requirements of the relevant OIML international recommendations. Certificates are delivered by OIML Member States that have established one or several issuing authorities responsible for processing applications. OIML certificates are accepted by national metrology services on a voluntary basis. Given the increasing national implementation of OIML guidelines, more and more manufacturers are referring to OIML international recommendations to ensure that their products meet international specifications for metrological performance and testing.

Why is it relevant?

By becoming a member of OIML, countries participate in the process of shaping model regulations in the field of legal metrology. OIML draft recommendations and documents are developed by Technical Committees or Subcommittees which are formed by the OIML Member States. In addition, the Certificate System for Measuring Instruments facilitates the administrative procedures associated with the international trade of measuring instruments subject to legal requirements. The OIML web site database lists those OIML Certificates registered by the BIML, and gives the list of categories of instruments covered by the System, the addresses of issuing authorities in OIML Member States, and those of recipients of Certificates (applicants and manufacturers).

Additional Information

Cooperative agreements are established between the OIML and certain institutions, such as ISO and IEC, with the objective of avoiding contradictory requirements.



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