Welcome to the OIML Website

The mission of the OIML is to enable economies to put in place effective legal metrology infrastructures that are mutually compatible and internationally recognized, for all areas for which governments take responsibility, such as those which facilitate trade, establish mutual confidence and harmonize the level of consumer protection worldwide.
The OIML is an “international standard-setting body” in the sense of the World Trade Organization's Technical Barriers to Trade Agreement. OIML publications should therefore be applied, when appropriate, by all signatories of the TBT Agreement when developing technical regulations, in application of Article 2.4 of that Agreement.

World Metrology Day 2023


World Metrology Day is an annual celebration of the signature of the Metre Convention on 20 May 1875 by representatives of seventeen nations. The Convention set the framework for global collaboration in the science of measurement and in its industrial, commercial and societal applications. The original aim of the Metre Convention - the world-wide uniformity of measurement - remains as important today as it was in 1875.

The World Metrology Day project is realized jointly by the BIPM and the OIML.

The theme for World Metrology Day 2023 is Measurements supporting the global food system.

This theme was chosen because of the increasing challenges of climate change, and global distribution of food in a world whose population reached 8 billion at the end of 2022.

Video by Mr Anthony Donnellan, BIML Director

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Joint BIPM/OIML Brochure on D 1


The BIPM/OIML Brochure, with six inserts on different aspects of the National Metrology Systems, was published within the frame of the BIPM and OIML joint knowledge transfer initiative.

The brochure has been developed from the BIPM and OIML joint publication - “National metrology systems - Developing the institutional and legislative framework” (OIML D 1:2020).

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Technical work

Publications development by
OIML TCs, SCs and PGs

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OIML Issuing Authorities,
Utilizers, Associates, Certificates

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Countries and Economies with
Emerging Metrology Systems

What is legal metrology?


Legal metrology is the application of legal requirements to measurements and measuring instruments. Very often, small errors in either direction average out over a large number of measurements. But biased errors can create considerable financial prejudice and can have serious economic consequences for the end consumer.

This is why legislation on measurements and measuring instruments is required and virtually all countries provide such protection by including metrology in their legislation – hence the term “legal metrology”...

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Legal metrology and the Environment

Legal metrology

and the Environment

We use measurements to obtain data which can then be used to help make the correct decisions to properly care for our environment

Legal metrology and Trade

Legal metrology

and Trade

The trade of goods and services around the world is vital for economic growth, for the wellbeing of the population, and to maintain worldwide financial stability

Legal metrology and Safety

Legal metrology

and Safety

Safety is often taken for granted, whether at home, at work or when traveling

Legal metrology and Health

Legal metrology

and Health

Population growth, longer life expectancy, increasing international travel and trade, and innovations in modern medicine are placing an ever growing demand on healthcare systems

What is the OIML Certification System?


The OIML-CS is a voluntary system for issuing, registering and using OIML Certificates and their associated OIML type evaluation/test reports for types of measuring instruments based on the requirements of OIML Recommendations.

The aim of the OIML-CS is to facilitate, accelerate and harmonize the work of national and regional bodies that are responsible for type evaluation and approval of measuring instruments subject to legal metrological control.

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