May 20 is World Metrology Day, commemorating the anniversary of the signing of the Metre Convention in Paris, in 1875. This treaty provides the basis for a worldwide coherent measurement system that underpins scientific discovery and innovation, industrial manufacturing and international trade, as well as the improvement of the quality of life and the protection of the global environment.
The theme for World Metrology Day 2025 is “Measurements for all times, for all people,” chosen to highlight the importance of measurements in shaping our past, present, and future. This theme has added significance in 2025, which marks the 150th anniversary of the Metre Convention.
As a tribute to this milestone, World Metrology Day 2025 will be at the core of events to celebrate a century and a half of international collaboration in metrology. From ensuring fair trade and advancing scientific discovery to addressing global challenges like climate change and public health, measurements have been fundamental for progress and innovation. The theme also emphasizes inclusivity, recognizing that reliable and traceable measurements are essential for fostering equity and improving the quality of life for all people, everywhere.
Around the world, national metrology laboratories continually advance measurement science by developing and validating new measurement techniques at the necessary level of sophistication. The national metrology institutes participate in measurement comparisons coordinated by the International Bureau of Weights and Measures (BIPM) or by the Regional Metrology Organizations (RMOs), to ensure the reliability of measurement results worldwide.
The International Organization of Legal Metrology (OIML) develops international recommendations, which aim to align and harmonize requirements worldwide in many fields. The OIML also operates the OIML Certification System (OIML-CS) which facilitates international acceptance and global trade of regulated measuring instruments.
These international metrology systems provide the necessary assurance and confidence that measurements are accurate, providing a sound basis for global trade today and helping us to prepare for the challenges of tomorrow.
World Metrology Day acknowledges and honors the contributions of individuals working in intergovernmental, regional, and national metrology organizations and institutes year round. In November 2023, a significant milestone was reached as the UNESCO General Conference, during its 42nd session, officially recognized the celebration on 20 May annually. Underscoring its pivotal role in advancing global scientific cooperation, this endorsement opens up new avenues to promote metrology, aligning with UNESCO’s mission to build a better world through science and education.