The Contrôle Officiel Suisse des Chronomètres—COSC— is a neutral, public-interest non-profit association dedicated to ensuring precision and reliability in Swiss watchmaking headquartered in La Chaux-de-Fonds, Switzerland. Since 1973, it has been the trusted authority behind the Certified Chronometer label. COSC-certified watches undergo rigorous testing, measuring time deviation across seven criteria in various conditions for 12 to 20 days. This process guarantees not only precision but also reliability in everyday situations, reflecting the quality of the tested movements.
Since its creation, the COSC has certified nearly 55 million movements, including 2.4 million in 2024 alone. Over 60 brands rely on the COSC, making it responsible for certifying around 40% of Swiss-made mechanical watches exported worldwide each year. After more than 50 years of dedication, the Contrôle Officiel Suisse des Chronomètres—COSC—, or Official Swiss Chronometer Testing Authority, is entering an exciting new chapter. With a refreshed positioning, a revitalized visual identity, and an unwavering commitment to promoting Swiss watchmaking excellence, COSC now extends its focus beyond Swiss watch brands, directly engaging with consumers.
COSC has been the standard-bearer for certifying the precision of watch movements. But it’s not just about accuracy—COSC guarantees the quality, reliability, and durability of every movement tested, earning it the prestigious “Certified Chronometer” label. Today, COSC brings together more than 60 renowned brands united by a commitment to excellence, further solidifying Swiss watchmaking’s global reputation. For consumers, owning a COSC-certified watch is an unquestionable mark of quality.
With a sleek new logo, updated signature, enhanced website, active social media engagement, and an informative newsletter, COSC is amplifying its message like never before. The objective is clear: to establish COSC as a distinct brand, not just a certification mark, while increasing visibility and trust among consumers.
"It's not just about redesigning a logo; it's about showcasing what we do best—fine watchmaking—alongside our client brands. Certified by our three independent laboratories and 160 operators, we uphold the highest standards of precision and excellence. We serve a shared customer, ensuring they receive timepieces of unmatched quality. By certifying precision, embodying excellence, and making it known, we contribute to the global reputation of the Swiss watchmaking industry," explains Andreas Wyss, Director of the COSC.
Looking ahead, COSC and its partner brands will introduce new certification cards that give consumers exclusive access to precise data about their watch's tested movement. As an independent authority, COSC offers the ultimate assurance—a rigorously tested, objectively measured timepiece that consumers can rely on. COSC’s mission is to unite its partner brands under a shared commitment to Swiss excellence.
These brands will benefit from enhanced visibility through COSC’s communication channels, as well as access to ready-to-use content to amplify their message. The growing recognition of COSC will allow brands to reach a broader consumer audience, backed by the authority and credibility of this global certification. Brands will also have access to the testing results for each movement, providing their customers with unique insight into the precision behind every timepiece.
More than just a certification, COSC is evolving into a true symbol of excellence.
