What is the Official Swiss Chronometer Testing Institute’s guilty pleasure? Literally putting watch movements through their paces. For about two weeks, (almost) nothing is spared: upside down, sideways, temperature variations... Every movement, or watch head (meaning the movement inside the case), undergoes a battery of rigorous tests to evaluate its accuracy according to different criteria. If successful, the candidate earns the “Certified Chronometer” certification, an exceptional label that the brand may choose to highlight on the watch and in its communications. Most importantly, the watch officially becomes an ambassador of Swiss watchmaking excellence, synonymous with precision, reliability, and durability. "If Swiss Made is the foundation, the Chronometer certification is its star," explains the COSC, which is also a non-profit and public utility association recognized in Switzerland.
Independent and neutral, just like... the COSC!
Its secret weapon? A distinctly Swiss soul, built on independence and neutrality. Its organization guarantees complete impartiality: no watch group or brand can interfere with the tests or influence the results. COSC also claims accessibility to its certification. Its rates remain the same for all, with no discounts for higher volumes, ensuring fairness between brands, whether niche or more renowned.
This uniqueness has won over the Swiss watch industry, which appreciates such a guarantee of superior quality. Today, the association includes around sixty brands. The numbers are revealing: nearly 40% of mechanical wristwatches exported from Switzerland have passed the COSC tests – that's 15% of all watches produced (including quartz watches). In this sense, the Chronometer certification remains rare. However, watches and movements tested by the COSC pass the challenge with a success rate of exactly 93%, demonstrating their great quality.
Behind these numbers, an impressive machine: over 2 million timepieces tested every year (2.4 million in 2024), across three laboratories (Bienne, Le Locle, St-Imier), with 160 employees working 7 days a week to ensure ongoing compliance with standards. Each test lasts between 12 to 20 days, depending on the type of watch.
A label finally in the spotlight
Until now, the COSC certification was highly valued by brands and insiders, but remained relatively confidential and unknown to the public. Today, COSC has chosen to become a brand in its own right, a signature inseparable from watchmaking excellence. Its new website – https://www.cosc.swiss/ – is educational and clear, pulling back the curtain on its inner workings. Furthermore, brands can access the results of each watch, providing an additional advantage in documenting the reliability, durability, and precision of a certified movement.
Watchmaking is characterized by its ability to adapt to the times, innovate, while remaining rooted in tradition. This time, it is not a brand reinventing itself, but the legendary COSC, a historical pillar of Swiss quality for more than half a century. This serves to strengthen the aura of Swiss Made watchmaking worldwide – and to position itself as an undeniable reference for fine craftsmanship.
