WORLD METROLOGY DAY - 20th May

Metrology, the field of knowledge applicable to measurement, cuts across all areas of engineering science and serves a wide range of technical, scientific and legal activities. It covers the realisation, development and maintenance of standards for units of measurement; the establishment of traceability of reference and working standards to be used by the scientific and industrial community; the assessment of the uncertainty of measurements made; the approval of measuring instruments for commercial, industrial and fiscal applications and other regulated areas, as well as the monitoring of instruments during their useful life.

World Metrology Day is celebrated every year on 20 May. This year, this celebration has a very special significance, as 2025 marks the 150th anniversary of the Metre Convention and the 70th anniversary of the International Organisation of Legal Metrology (OIML).

The celebration of a century and a half of international collaboration in the field of Metrology is alluding to the theme ‘Measurement for all times, for all people’, with a special focus on inclusion, recognising that reliable traceable measurements are essential for promoting equity and justice, and improving the quality of life for all.

UNESCO's recognition of World Metrology Day also reflects its essential role in the development of global scientific cooperation, enabling new ways to promote metrology, in full articulation with UNESCO's mission to build a better world for science and education. It is thus a day that marks an important milestone in the history of science.