World Metrology Day 2025

World Metrology Day takes place on May 20, 2025, and is celebrated by more than 80 countries around the globe. The day celebrates the signing of the Metre Convention on that day in 1875 in Paris with representatives of 17 nations attending. Until today, this agreement provides the basis for a single, coherent system of measurements, and therefore the worldwide uniformity of measurement, that are traceable to the International System of Units (SI). Today the World Metrology Day is realized by the International Bureau of Weights and Measures (BIPM), the International Organization of Legal Metrology (OIML), and the PTB International Technical Cooperation.

More dates:

• World Metrology Day on May 20, 2026
• World Metrology Day on May 20, 2027
• World Metrology Day on May 20, 2028